Definition of MacGuffin (or McGuffin): The famed director Alfred Hitchcock often capitalized on a gimmicky plot element to catch the viewer's attention or serve as a distraction - dubbed a McGuffin (or MacGuffin), that would propel the plot along its course. It is essential that a MacGuffin is introduced early in a film, and that it is something that has no real identity of its own and could be interchangeable.

Usually, the MacGuffin initially appeared to be of utmost importance as a catalyst - something that everyone in the plot wanted or was chasing, but actually was unimportant and only functioned to intentionally misdirect the audience. The MacGuffin then quickly faded into the background and ended up being trivial, irrevelant, insignificant or incidental to the film's story by its ending.

Its derivation was Scottish, meaning a "lion trap" for trapping lions in the lion-less Scottish Highlands (i.e., a trap that means nothing, since it is for an animal where there is no such animal). Not every Hitchcock film had a MacGuffin.

The MacGuffin normally refers to the mystery to be solved (or the fugitive's innocence to be proven), or a tangible object (in high demand for some reason, such as jewelry, a piece of evidence, a corpse, a person, a secret formula or message, a statuette or a military secret, something being smuggled, etc.), or some other kind of goal or motivator. MacGuffins are distinct from other film elements such as plot devices.

• The Maltese Falcon (1941): the fabled black bird itself
• Citizen Kane (1941): Charles Foster Kane's final word - "Rosebud"
• Casablanca (1942): the "letters of transit"
• It's A Mad, Mad, Mad, Mad World (1963): the big "W"
• Monty Python and the Holy Grail (1975): the Holy Grail
• Star Wars (1977): the schematic plans for the Death Star
• Apocalypse Now (1979): Colonel Kurtz
• Escape From New York (1981): a cassette tape containing information about nuclear fusion
• Star Trek II: The Wrath of Khan (1982): the Genesis, a powerful terraforming device
• Romancing the Stone (1984): the emerald stone

• Pulp Fiction (1994): Marcellus Wallace’s briefcase
• Beavis and Butt-Head Do America (1996): the X-5 bioweapon
• Titanic (1997): the rare diamond necklace, the Heart of the Ocean
• The Big Lebowski (1998): the Dude's Persian Rug
  
• Saving Private Ryan (1998): Private Ryan himself
• Crouching Tiger, Hidden Dragon (2000): the Green Destiny Sword
• The Lord of the Rings (2001-2003): the "One Ring"
• The Departed (2006): stolen missile guidance microchips
• Mission: Impossible III (2006): a toxic weapon known as "the rabbit's foot"
• Avatar (2009): the mineral energy source "unobtanium"
• The Hangover (2009): the missing Doug

• the MacGuffin: a pair of women's gloves found at the crime scene
• in the story, a London woman named Alice White (Anny Ondra) murdered an artist (of harlequins) named Mr. Crewe (Cyril Ritchard) who tried to rape her in his Chelsea art studio; she defended herself with a bread-knife and stabbed him to death; as she fled his studio, she accidentally left behind her gloves
• Scotland Yard Detective Frank Webber (John Longden), Alice's beau-boyfriend, was coincidentally assigned to investigate the homicide case; at the crime scene, when he located one glove and realized it belonged to Alice, he concealed it from other colleagues, knowing that it would incriminate Alice as the killer
• Alice's blackmailer was petty criminal Tracy (Donald Calthrop), who had seen Alice enter Crewe's studio; he claimed that he possessed the second glove; he made payment demands that were confronted by Frank - who was determined to cover up for Alice's misdeed
• as a suspect, Tracy fell to his death at the British Museum during a chase, while Alice was considering turning herself in to authorities; she wrote a note to Frank: "I am going to give myself up. I cannot bear the thought of that man being accused of something I have done"
• the police assumed that Tracy was Crewe's murderer; she confessed the truth to Frank ("I did it") and he replied: "I know"; she then explained how it was self-defense: "I was defending myself - I didn't know what I was doing"

• the MacGuffin: a jeweled, diamond Suffolk necklace stolen by a gang of thieves in London (Amhurst Park), and located in a safe-house hideout on Anderson Road known as "Number Seventeen"
• in the expressionistic opening set in a dilapidated and abandoned mansion with cobwebs (a "house for sale or let" at No. 17), a body was discovered on the floor (with handcuffs and a gun) by a Cockney homeless man named Ben (Leon M. Lion) and an undercover detective named 'Barton' (revealed at the end to be Detective Gilbert Fordyce (John Stuart) (aka Forsythe))
• shortly later, policeman’s daughter Rose Ackroyd (Ann Casson) (a neighbor at No. 15) fell through the rotting roof of the home; she claimed she was looking for her father Mr. Ackroyd (Henry Caine), who disappeared from their home just before she received a telegram -- "Have Traced Suffolk Necklace to Sheldrake - Expect Him to Make Getaway Tonight - Watch NO 17 - Will Arrive Later – Barton" -- the telegram from 'Barton' referred to a stolen necklace and jewel thieves (led by 'Sheldrake' (Garry Marsh)) who were lured for an anticipated rendezvous at the house at around midnight before their escape via a trap door to a railway siding
• suddenly, the body on the floor disappeared - it was actually 'Sheldrake' pretending to be dead; he was seen removing the necklace from the water-tank of a toilet, but then Ben pickpocketed the necklace from 'Sheldrake's' pocket
• a trio of individuals (thieves looking for the necklace, posing as house hunters) arrived at the house at 12:30 am: (1) the gang leader's girlfriend Nora (Anne Grey), pretending to be mute, (2) Nora's escort-husband Brant (Donald Calthrop), and (3) their nephew, Henry Doyle (Barry Jones) (who falsely claimed in the film's conclusion he was posing as 'Barton')
• in the final scene, Ben revealed that the necklace was safe around his neck and offered it as a wedding present in exchange for a ride, as he spoke to Detective 'Barton'/Forsythe and Nora: "Will you see me safely home, guv'nor, if I gives you a nice wedding present, eh?"

• the MacGuffin: the planned assassination attempt of a foreign dignitary that was to take place in London (seen in a secret message intended for the British consul)
• in the plot, during a skiing holiday in St. Moritz (Switzerland) taken by the Lawrence family, Bob Lawrence (Leslie Banks) with his wife Jill (Edna Best), a French skier named Louis Bernard (Pierre Fresnay) was shot and killed during dinner; as he expired, he whispered to Jill that in his hotel room, he had a shaving brush containing a message that must be given to the British consul
• the enigmatic and cryptic note contained a place name (WAPPING) and two names: G. BARBOR MAKE CONTACT A. HALL MARCH 21st.
• it was revealed that Louis Bernard had been an agent for the "Deuxieme Bureau" and had been in the process of preventing the assassination of a world leader-statesman
• meanwhile, the Lawrence's daughter Betty (Nova Pilbeam) had been kidnapped; under time pressure to find his daughter and not upset the terrorists, Bob went in pursuit of the clues in the note; he realized that he had misunderstood, through concert tickets, that A. Hall was not a person but a place (Royal Albert Hall), and the assassination was to occur there at the end of the orchestral performance during a clash of cymbals, by a sharpshooter-assassin named Ramon (Frank Vosper)

• the MacGuffin: the nature of the '39 Steps' (What did 'the 39 Steps' refer to? Was it an organization or a thing?)
• the British possessed military secrets - secret airplane engine plans (vital to the country's air defense) that spies were attempting to smuggle out of the country in the mind of a music hall mentalist named Mr. Memory (Wylie Watson)
• in the concluding scene set in London's Palladium, it was revealed that the memory expert on stage held the Hitchcockian "MacGuffin" in his head - he had memorized the classified secret information regarding mechanical plans for the design of an airplane engine: "The details of the Air Ministry secrets were borrowed, memorized by this little man, and then replaced before anyone could find out" - and after the evening's show, Mr. Memory was to be taken out of the country by the spies, led by Professor Jordan
• when the hero Richard Hannay (Robert Donat) shouted out the question: "What are the Thirty-Nine Steps?", Mr. Memory dutifully answered: "The Thirty-Nine Steps is an organization of spies, collecting information on behalf of the foreign office of..." - but before he finished and named the country, Mr. Memory was silenced with a gun shot that rang out from master-spy Professor Jordan's (Godfrey Tearle) box above the stage; backstage as he died, Mr. Memory "confessed" by proudly reciting the complicated scientific mathematical formulas of the secret documents that he had painstakingly memorized - the secret formula was about how to make silent aircraft engines

• the MacGuffin: the belt (used for strangulation) from a missing (stolen?) raincoat
• in the plot, the body of international film star-actress Christine Clay (Pamela Carme) washed up on an English coastal seaside; her death came the morning after an argument with her jealous and estranged ex-husband Guy (George Curzon), who still wanted to be married to her (he said her Reno divorce wasn't valid), and accused her of having affairs; incensed, he looked out at the sea from the balcony, and turned back with rapidly-twitching eyes at his ex-wife (angered and capable of foul play)
• at the scene of the crime, screenwriter Robert Tisdall (Derrick De Marney) spotted the body and ran off to notify authorities; police had determined that Christine was strangled with the belt from a raincoat
• there were three reasons for Tisdall to be considered a prime suspect, although he was wrongly-accused: (1) he was seen running away from the crime scene, (2) Tisdall claimed that his raincoat was recently stolen and was missing, and (3) Christine had left him £1,200 pounds in her will (unknown to him), suggesting that they were romantically involved with each other
• Erica Burgoyne (Nova Pilbeam), the daughter of local police chief Colonel Burgoyne (Percy Marmont), believed in Robert's innocence; an intense search occurred, with her help, to search for and retrieve his raincoat to prove his alibi (if his coat still had its belt, the one found next to Christine's body wouldn't be his); when they questioned a local vagrant and China-mender named Old Will (Edward Rigby) who had the raincoat, it was learned that Will was given the coat (without a belt) by a man with twitching eyes
• in the conclusion, a matchbook in the pocket of the coat led to the Grand Hotel, where the killer (with the tell-tale twitching eyes) was finally spotted - he was a blackfaced drummer in a minstrel dance band (concealing his looks) in the hotel's ballroom; when confronted after collapsing, he confessed to the murder of Christine and Robert was cleared

• the MacGuffin: the secret message encoded in a piece of music sung by a folk singer-musician on the street - listened to and remembered by Miss Froy (May Whitty) - and then the singer was soon after murdered by strangulation - why was the singer murdered?
• another MacGuffin: the identity (and location) of the kidnapped or disappearing elderly lady Miss Froy - why did she vanish?
• in this tale, the person carrying the 'secret' information disappeared (or was kidnapped) and the search for their 'secret' became a search for the person
• there was evidence! that Miss Froy existed - she had written her name on the steamed-up carriage train window, proving that Iris Henderson's (Margaret Lockwood) claim that Miss Froy existed wasn't just an hallucination, but then grime from a train tunnel covered up the evidence
• in the final scene, Miss Froy was seen in the British Foreign Office in Whitehall, playing the tune on a piano

• the MacGuffin: the character of the first Mrs. de Winter - Rebecca (never seen on screen) - did husband Mr. Maxim de Winter (Laurence Olivier) really love her or not, and was he responsible for her death?
• the haunting presence of keepsakes and the hallowed memory of Rebecca de Winter, continually mentioned lovingly by housekeeper Mrs. Danvers to drive the second Mrs. de Winter (Joan Fontaine) crazy
• the startling confession given by Maxim to his second wife, about how he despised Rebecca; when she asked: "How could I even ask you to love me when I knew you loved Rebecca still?" - he replied with vehemence: "You thought I loved Rebecca? You thought that? I hated her!... I never had a moment's happiness with her. She was incapable of love, or tenderness, or decency"; the second wife replied with disbelief - and relief: "You didn't love her? You didn't love her?"
• the death of Rebecca (how she died) - was revealed by her doctor Dr. Baker (Leo G. Carroll) and her husband to be intentional - realizing that she was terminally ill, she deliberately goaded Maxim into accidentally killing her; Maxim was acquitted of her murder, and her death was ruled as a suicide

• the MacGuffin: the secret Clause 27 in a peace treaty between Holland and Belgium, memorized by Dutch diplomat Van Meer (Albert Bassermann) who was one of only two signatories of the treaty; the most important clause in the treaty was never written down, just memorized by the two; therefore, it was "a piece of information that would be very valuable to the enemy in the war that breaks out tomorrow, weather permitting"; the secret clause in the treaty could either be used to avert or start the war
• in the plot, American crime reporter and 'foreign correspondent' Johnny Jones (Joel McCrea) was selected to interview Van Meer: "Talk with him, find out what's in that treaty, and what he thinks is gonna happen. Facts!"
• in the film's most striking sequence set on steep stair steps leading down from the Amsterdam Town Hall to the public square, Jones became suspicious when diplomat 'Van Meer' (Samuel Adams), whom he had already met and talked to in London, failed to recognize him even after repeated reminders; at the same time, a press photographer (Charles Wagenheim) stepped up to them and asked permission for the diplomat's photograph - a gun was concealed or hidden by his camera, and the assassin shot 'Van Meer' to death at point-blank range in the middle of his forehead; he tumbled down the steps
• however, as it was revealed a bit later in a windmill outside Amsterdam, the real Van Meer was alive; the man shot was Van Meer's impersonator, look-alike decoy or doppelganger; as a result of the real diplomat's knowledge, he had been kidnapped after the faked assassination attempt by a secret international peace organization operating as a subversive Nazi spy ring; he admitted what had happened to Jones before being taken away: "The man you saw shot, it wasn't me. He was a substitute that looked like me...They want the world to think that I've been assassinated. Yes. To conceal the fact that I'm in their hands"
• the film revolved around trying to locate and save the diplomat ("Holland's strongman") (and prevent his torture) - he was allegedly the key to maintaining peace in Europe in 1939
• in the long run, the MacGuffin became unimportant when Van Meer was rescued (and the leader of the spy ring was uncovered); the film ended with reports that Germany had invaded Poland and Denmark, and was bombing Norway

• the MacGuffin: the overriding question: was playboyish, irresponsible, untrustworthy, and penniless con-artist and gambler Johnnie Aysgarth (Cary Grant) also a killer or not? did he marry his wife just for her money? was he plotting his rich wife's murder?
• Johnnie's wife Lina McLaidlaw-Aysgarth (Joan Fontaine) continually suspected that her husband was going to murder her - when he played word games, all she could see was the word 'murder,' and when he read a book about a killer, she thought it was a manual for his own deeds to poison her
• the character of naive Englishman 'Beaky' Thwaite (Nigel Bruce), Johnnie's friend and financial partner - was the catalyst that caused Lina to ultimately suspect that husband Johnnie was a murderer, when 'Beaky' was found dead, traveling with Johnnie; after Lina learned of the death, the skylight above her in the hallway cast a web-like shadow over her as if she was in a cage - and the next victim?
• in the "glass of milk" sequence, Johnnie brought bed-ridden Lina a glass of milk (was it poisoned?), ascending the stairs with the luminous glass
• however, by film's end in a tacked-on ending, it was revealed that Lina had been entirely wrong about Johnnie; he was planning on taking out a life insurance policy on himself and then committing suicide, in order to cover his debts

• the MacGuffin: the elusive whereabouts of Frank Fry (Norman Lloyd), an arsonist-saboteur who was part of a cabal of 'fifth columnists' and terrorists who were plotting to destroy Hoover (Boulder) Dam and a USS naval battleship in Brooklyn, among other things, including in the first scene the burning of a Los Angeles defense aircraft factory

• the MacGuffin: incriminating items that would reveal the evil identity of Charles Oakley (Joseph Cotten), a serial murderer (of rich widows for their money) shown in the opening sequence
• upon arrival in Santa Rosa, CA, homicidal Uncle Charlie gifted a stolen emerald ring to Young Charlie Newton (Teresa Wright) with incriminating initials engraved inside - a major MacGuffin
• after Young Charlie's sleuthing at the library to read the days' newspaper (her family's paper had been destroyed by Charlie) - she came upon an article about the 'Merry Widow' murderer; she learned that the MW Murderer's third victim's name matched the engraved initials on the ring Uncle Charlie gave her (TS From BM): TS (Thelma Schenley) From BM (Mrs. Bruce Matthewson) - the film's major turning point

• the MacGuffin: the many mysterious instances of parallel lines (fork lines on the tablecloth, train tracks, a bank teller's bars, robe stripes, patterns on a bedspread, and sledding tracks outside a window) - and the search for their real meaning
• why did the lines or patterns haunt and agitate the sanity of the replacement head for Green Manors, a Vermont psychiatric hospital - a young Dr. Anthony Edwardes (Gregory Peck)? -- was it due to a forgotten murder from the past?
• the MacGuffin, in essence, was Dr. Edwardes' memory of his past and some traumatic event
• Dr. Constance Petersen (Ingrid Bergman), the hospital's only female psychologist - discovered that the signature on the note slipped to her by Dr. Edwardes was markedly different from his autograph in his book (Labyrinth of the Guilt Complex); she suspected he was a fraud, although was falling in love with him
• through sleuthing and psychoanalyzing his phobia (or "guilt complex"), Dr. Edwardes came to cured; he admitted he was an imposter (his real name was John Ballantyne or J.B.), had amnesia, was on-the-run, and had possibly killed the real Dr. Edwardes; he also remembered a traumatic childhood incident of pushing his brother off a bannister, accidentally causing him to be impaled by the spires of an iron gate; his recovered memory revived him and inspired him to save Constance from skiing off the same steep slope on which Dr. Edwardes, in JB's presence, fell to his death
• the MacGuffins in the story ultimately climaxed to reveal the unmasking of the real killer of Dr. Edwardes, Dr. Murchison (Leo G. Carroll), the long-time head of the institution who didn't want to be retired; he had shot Dr. Edwardes on the ski slope

• the first MacGuffin: the importance of the key to the mansion's wine cellar - only one key existed, and it was in the possession of Nazi sympathizer Alexander Sebastian (Claude Rains) in Brazil; Alex's wife Alicia Huberman (Ingrid Bergman) took the wine cellar key off Alex's key ring and passed it to Devlin (Cary Grant)
• the second main MacGuffin: radioactive material (uranium ore or "vintage sand") found in a locked cellar's wine bottles that was being smuggled; it was discovered when one bottle smashed onto the floor and revealed uranium powder being mined in the mountains of Brazil by the Nazis
• another very secondary MacGuffin was the poison in the coffee used to slowly kill Alicia

• the MacGuffin: the whereabouts of David Kentley (Dick Hogan), continually the main item of discussion in the film by guests at a dinner party
• (David's corpse had been stuffed into an old wooden chest in the middle of the room - that was to be used as a buffet table!)
• tension was created because the body might be discovered at any moment by the guests
• another MacGuffin: the rope - out in the open - used for the strangulation murder of David, and then dangled about and used to tie up a bundle of books
• a secondary MacGuffin: the wrong hat (the victim's monogrammed hat) picked up by Rupert (James Stewart)

• the MacGuffin: the blood-stained dress - allegedly worn by stage actress/singer Charlotte Inwood (Marlene Dietrich) when she murdered her husband
• Charlotte's secret lover was another actor named Jonathan Cooper (Richard Todd); in a flashback, he claimed that Charlotte was wearing the blood-stained dress, and came to his door to confess right after killing her husband during a quarrel; in his account, he described how he went back to her house to get her a clean dress, and also arrange the murder scene to make it look as if there had been a robbery; however, he had to flee when Charlotte's maid Nellie Goode appeared and identified him
• Jonathan became the prime suspect - but was he framed by Charlotte, or was he really involved? - as Jonathan evaded police, an investigation commenced, and at times, it appeared that Charlotte was the guilty one
• in the conclusion, it was revealed that Charlotte had conspired to kill her husband, but it was Jonathan who had committed the deed (with Charlotte present); he admitted that his earlier 'flashback' story was a lie - he was the one who had smeared blood onto the dress, and had killed her husband out of jealousy when Charlotte ended her relationship with him

• the MacGuffin: Guy Haines' (Farley Granger) cigarette lighter, monogrammed with "A to G" and with a symbol of two criss-crossed tennis rackets -- it was a gift from Guy's girlfriend Anne Morton (Ruth Roman) to him
• the lighter was to be used as incriminating evidence, to be planted by villainous psychotic Bruno Antony (Robert Walker) in order to frame Guy for murder
• in the conclusion, as Bruno died from being crushed under a carousel, he refused to clear Guy, but his hand opened - revealing Guy's lighter (and innocence)

• the MacGuffin: the privileged or confidential information wanted by the police - a Catholic confession
• the information was contained in an admission-confession given by sexton Otto Keller (O.E. Hasse), a German immigrant and housekeeper; he made the confession (of an accidental murder of crooked lawyer Vilette (Ovila Légaré)), to his Catholic priest Father Michael Logan (Montgomery Clift) in Quebec City

• the MacGuffin: the duplicate latch-keys to the Wendice apartment - especially the one hidden under the stair carpet outside the apartment - the one that incriminated Tony Wendice (Ray Milland) in the final scene when he let himself in with the stair's key - revealing that he had designed the murder plot against his wife
• the key under the stair's carpet was his wife Margot’s (Grace Kelly) own duplicate house key, which Tony snuck out of her handbag and put under the stairway carpet outside their door - it was put there to let wife-murderer Capt. Lesgate/Swann (Anthony Dawson) into the apartment, in a plot with Tony
• during the murder, Lesgate was specifically instructed to enter with the key, commit the murder, then exit out the way he came, lock the door, and replace the key under the stairs - however, after opening the door, Swann returned the key to its hiding place immediately
• during the investigation after the botched murder, Tony made an incorrect assumption - he postulated inaccurately that Swann must still have Margot's latch-key (from the stairs) on him in his pocket; so he surreptitiously took the key from Swann's pocket (Swann's own apartment key) and placed it back in Margot's purse; this mistake would ultimately lead to a self-incriminating display of his own guilt

• the MacGuffin: the suspected 'murder' committed by apartment tenant and traveling salesman Lars Thorwald (Raymond Burr) across the courtyard, of his bed-ridden wife Mrs. Emma Thorwald (Irene Winston)
• the lingering question: what happened to her?
• there was circumstantial evidence that was slowly pieced together (a saw and butcher knife wrapped in newspaper, the moving of a heavy trunk, the removal of jewelry from the wife's handbag, a strangled dog that had snooped in the courtyard's garden, etc.)

• the MacGuffin: the identity of the cat-burglar who committed a daring, night-time burglary (jewel theft) in the opening sequence set on the Riviera - the perpetrator was suspected to be reformed burglar John Robie (Cary Grant) (nicknamed "The Cat")
• in the film's conclusion during a costume ball, Robie finally proved he was innocent and caught the real masked copycat thief - young blonde Danielle Foussard (Brigitte Auber), who was dangled from the roof until she confessed that her father Foussard (Jean Martinelli) and restaurateur Bertani (Charles Vanel) had planned all of the robberies [Note: Danielle was the daughter of the head waiter at Bertani's restaurant]

• the MacGuffin: the corpse, found on a hill in the Highwater, Vermont forested countryside
• there were many diversionary elements to the murder mystery plot and its MacGuffin - the frantic search of townsfolk (some of whom believed they were guilty) to learn:
  - WHAT or WHO killed the victim
  - HOW did the victim die
  - WHO was the victim (identified as Harry Worp from Boston, played by Philip Truex)
• the story's plot told more about its characters and their relationships than about the central (and titular) dead man - a perfect MacGuffin
• the main dilemma (a story of cover-up) turned out to be: WHAT TO DO WITH THE BODY (that was buried and redug up several times to avoid police charges) - especially to conceal it from being discovered by Deputy Sheriff Calvin Wiggs (Royal Dano)
  
• in the conclusion, the town's Dr. Greenbow (Dwight Marfield) announced that Harry died of natural causes - presumably a heart attack, although the corpse had a bump on its head, and Jennifer Rogers (Shirley MacLaine) admitted that at her doorstep that morning, she had whacked Harry (her second ex-husband who abandoned her) with a milk bottle in the head (and he presumably staggered up into the forest and died)

• the MacGuffin: it was the warning (a whispered message from a dying man) that there was to be an assassination of a foreign statesman in London - and that the authorities must know about "Ambrose Chappell"
• in the plot, the McKenna family, Dr. Ben McKenna (James Stewart) and his famous singer-wife Jo Conway McKenna (Doris Day), while in Marrakesh, French Morocco, became acquainted with French businessman Louis Bernard (Daniel Gelin); the next day in the town square during an acrobatic show, a dark-skinned man lethally wounded in the back with a knife stumbled into Ben's arms and whispered: "A man, a statesman is to be killed...assassinated...in London, soon, very soon. Tell them in London to try...Ambrose Chappell"; the man was Louis Bernard in disguise; Ben transcribed the man's words, later given on a note to Jo; it was revealed that Bernard was a known agent of the Deuxieme Bureau (the French version of the FBI)
• after their young son Hank McKenna (Christopher Olsen) was kidnapped, the couple returned to London where Ben received anonymous phone calls and was pressured to keep silent; nonetheless, Ben went on a search for a person named 'Ambrose Chappell'
• it was Jo who understood that 'Ambrose Chappell' was an actual place, Ambrose Chapel, where she and Ben found further clues to the assassination plot
• the film climaxed during a performance at the Royal Albert Hall where the assassination attempt of the foreign prime minister was thwarted

• the MacGuffin: would Stork Club musician 'Manny' Balestrero (Henry Fonda) ever be cleared of the crime (assault and robbery) he allegedly committed?
• Christopher Emanuel “Manny” Balestrero was arrested on suspicion of robbery of an insurance company, and due to circumstantial evidence (a spelling mistake, and his similar appearance to the actual criminal) was arrested and booked - he was only released after the real crook was apprehended for robbing a delicatessan and clearly was 'Manny's' double in a case of mistaken-identity

• the MacGuffin: the spirit of a dead woman known as Carlotta Valdes, motivating obsessed Scottie Ferguson (James Stewart) to investigate what possessed or haunted his beloved but now-dead Madeleine Elster (Kim Novak), Carlotta's great-granddaughter
• a suspicious link between Carlotta and Judy was established when Judy (who was dressed to look like Madeleine at Scottie's insistence) decided to wear Carlotta's red-ruby heirloom necklace (it revealed that Judy was involved in the on-going deception of pretending to be Madeleine, who actually didn't exist)
• two secondary MacGuffins: Madeleine herself (non-existent), and Scottie's crippling fear of heights and vertigo

• the MacGuffin: the existence of CIA agent "George Kaplan" (mistakenly thought to be Cary Grant's character Roger Thornhill) who was being chased by spies, but 'George Kaplan' didn't really exist
• the true definition of a MacGuffin - was revealed to be the central nature of Roger O. Thornhill's identity, based upon his own initials: R-O-T - with the middle initial implying "nothing"
• another MacGuffin: "government secrets" on microfilm were hidden in a Pre-Columbian statue of a warrior that was being smuggled out of the country by the spies, led by Philip Vandamm (James Mason)

• the original MacGuffin: $40,000 of stolen money (in an envelope), taken from the realtors' Phoenix office by employee Marion Crane (Janet Leigh), who intended to run off with her debt-ridden lover Sam Loomis (John Gavin)
• at the Bates Motel run by nervous, suspicious and creepy proprietor Norman Bates (Anthony Perkins), Marion had second thoughts and regrets about the theft and was planning on returning the $40,000 the next day
• the money was ultimately wrapped up in a newspaper in the motel bedroom - discarded, and sunk in the trunk of the murdered Marion's car into a swamp, by Norman, to allegedly cover up for the stabbing shower murder of Marion by a female figure (his mother?) wielding a knife
• a new MacGuffin then surfaced - the apparent existence of Norman's invalid, bed-ridden mother who lived in the house perched on the hill behind the hotel - she might be able to help in the search for the whereabouts of Marion; and then came a second brutal murder; Detective Milton Arbogast (Martin Balsam) was assaulted at the top of the stairs - again by the knife-wielding, dress-wearing figure; was Norman's mother (Mrs. Bates) responsible for both murders?
• the entire plot was upturned when the town's Sheriff Chambers (John McIntire) described how Mrs. Bates had died over ten years earlier in a double-murder suicide: ("Well, if the woman up there is Mrs. Bates, who's that woman buried out in Greenlawn Cemetery?")

• the main MacGuffin: the unexplained cause, explanation or reason for the strange bird attacks in the town of Bodega Bay - hypothesized by many in the Tides Restaurant attack sequence; however, ultimately, there was no solid, rational reason why the birds were attacking - they were not seeking revenge for nature's mistreatment, or foreshadowing doomsday, and they didn't represent God's punishment for humankind's evil
• one of the more insightful reasons given was an hysterical mother's (Doreen Lang) vicious attack on rich and glamorous socialite Melanie Daniels (Tippi Hedren) for bringing some kind of chaotic "evil" into town: "Why are they doing this? Why are they doing this? They said when you got here, the whole thing started. Who are you? What are you? Where did you come from? I think you're the cause of all this. I think you're evil. (Shrieking) EVIL!"
• earlier in the film, it was noted that Melanie was known for destructive and expensive practical jokes that often back-fired on her ("Don't you remember one of your practical jokes that resulted in the smashing of a plate-glass window?"), and later, Melanie's notorious reputation as a jet-setting rich socialite was recollected in another scandalous report about her cavorting naked (as a jaybird?) into a fountain (birdbath?) in Rome the previous summer
• the underlying MacGuffin: the nature of the conflicted romance between Melanie Daniels and Mitch Brenner (Rod Taylor) - symbolized by a gift of two love-birds; the attacks were mysteriously related to the mother and son relationship in the film - Mitch's jealous, initially hostile mother Lydia Brenner (Jessica Tandy) expressed anger (and fears of abandonment or being left lonely) that came to the surface when her bachelor son Mitch brought home the attractive young Melanie
• it was clear that the "birds" (females) in the film, including Lydia, Melanie, and the town's schoolteacher Annie Hayworth (Suzanne Pleshette) (Mitch's former girlfriend) were circling and flocking around, seeking attention and affection from the sole, emotionally-cold male lead

• the MacGuffin: thunderstorms and the color red that triggered or caused deep-rooted psychological problems and neuroses for Marnie, but why?
• it was eventually explained that Marnie experienced extreme childhood trauma - seen in flashback - that occurred during the murder of her mother's abusive sex partner, drawing red blood
• the revelation of the root of Marnie's problems occurred in the Baltimore home of her crippled mother Bernice Edgar (Louise Latham) during a thunderstorm; she remembered (and relived) how her prostitute-mother's leg was broken by a Sailor client (Bruce Dern), and to come to her mother's aid, she struck the Sailor on the head with a fireplace-poker and killed him; subsequently, her mother took the blame for the crime

• the MacGuffin: the secret formula of mathematical equations (known by East German scientist and Professor Gustav Lindt (Ludwig Donath)) for an anti-nuclear device or anti-missile defense rocket that the East Germans had been developing to compete with the American anti-missile program known as "Gamma Five"
• Professor Lindt, a member of a secret spy ring that had defected to E. Germany, was tricked by US physicist and rocket scientist Michael Armstrong (Paul Newman) into divulging the entire complicated equation on a classroom blackboard; the scientist boasted: "But it works! In Russia we built it, it works!"; Armstrong congratulated him: "My God. That's brilliant. You jumped a step, didn't you?"; the Professor bragged: "Of course it's brilliant. It's genius. The Russians thought I was crazy. They didn't know I'm Lindt"; but then realizing his mistake and that he had revealed everything without learning anything himself, he mused: "You told me nothing. You know nothing" - he ordered Armstrong: "I forbid you to leave this room"

• the MacGuffin: the identity of Topaz -- What or who was Topaz? Who was in Topaz? What was its function?
• Topaz was revealed to be the code-name for a Soviet spy ring working in France, or the name of a Communist mole in the French government, leaking documents to the Soviet KGB
• in the film, Topaz (French traitors) were exposed by high-ranking Soviet intelligence officer Boris Kusenov (Per-Axel Arosenius), a defector to the West
  • Jacques Granville (Michel Piccoli) was the leader, code-named 'color-blind'
  • NATO official Henri Jarré (Philippe Noiret) was second in command
• another MacGuffin: visiting Cuban revolutionary Rico Parra's (John Vernon) red leather briefcase held NATO diplomatic documents ('aide memoire') - secret Russian plans for Cuba that were signed between the Soviet Union and Castro's Cuba - photos were secretly taken of the documents
• another MacGuffin-esque element in the film: the microfilm (hidden in a slim volume of poetry) that revealed the unloading of Soviet missiles in Cuba (seen in pictures taken by underground members Carlotta and Pablo Mendoza); the evidence was given to French intelligence Chief André Devereaux (Frederick Stafford) by his undercover counter-revolutionary mistress Juanita (Karin Dor) before he left Cuba

• the MacGuffin: the necktie-killer Bob Rusk's (Barry Foster) distinctive tie pin (with the initial R inset with diamonds) - it had to be removed from his tie before he raped and strangled his female victims
• the tie-pin was left behind at the scene of the crime after the killing of Barbara "Babs" Milligan (Anna Massey) - it was clenched in her corpse's hand (her stiff body suffering from rigor mortis was stuffed in a potato sack and loaded into the back of a truck-lorry); Rusk was forced to jump into the back of the lorry and pry open her hand to retrieve the tie-pin, as the vehicle moved along during the night - a tense sequence
• in the conclusion, Rusk was found about to deposit his latest half-naked female victim into a trunk for disposal; he was pointedly asked by Chief Inspector Timothy Oxford (Alec McCowen): "Mr. Rusk, you're not wearing your tie"

• the MacGuffin: the search in California for a nephew named Edward Shoebridge
• during a seance session in the home of elderly spinster Julia Rainbird (Cathleen Nesbitt) conducted by 'Madame' Blanche Tyler (Barbara Harris), Julia confessed that her deceased sister Harriet had borne an illegitimate son 40 years earlier who was then adopted by the Shoebridges and had become estranged from the family; Julia feared that the missing heir, named Eddie Stonebridge, was angry and deserved part of her inheritance fortune
• it was discovered that Eddie, who had his adoptive parents murdered and faked his own death (there was an empty grave and tombstone dated 1950), was now posing with a new name in San Francisco: Arthur Adamson (William Devane) (nicknamed "The Trader") and operated a jewelry store in the city
• the subplot: Adamson, with his wife Fran (Karen Black) was kidnapping rich or wealthy persons, followed by the demand for ransoms (of gemstones and diamonds)
• in the conclusion, the location of the stolen jewels was discovered by Blanche - a crystal chandelier in the Adamson home, near the staircase where they wouldn't be noticed