The private detective's next interview takes place in the Hillcrest Hotel, a cheap boarding hotel, with opera singer Carmen Trivago (Fortunio Bonanova) - a friend of the murdered Nicholas Raymondo. In Trivago's shabby place, a clothesline is cheaply strung across the center of the room, as the singer accompanies a Caruso recording of the Flotow opera Martha. To pressure a reticent Trivago into talking about the murdered scientist Raymondo, Hammer arrogantly and sadistically breaks into two pieces one of Trivago's prized "collector's item" Caruso 78 rpm recordings of Pagliacci - an act of extortion:

Trivago: Please, what do you want to know. I will tell you. I will tell you. Raymondo is my friend, you know. Very sad friend. Always sad. He's, how you call, engineer/scientist. Very smart, very bright. Very sad.
Hammer: He was murdered. Why was he murdered?
Trivago: I don't know. I don't know.
Hammer: What was he so sad about?
Trivago: Well, for the way the world is. You see, very sad.

Apparently, the engineer/scientist Raymondo was murdered by conspirators, because he knew but wouldn't talk about something that they wanted: "Somewhere, he has a secret...something small, something he can hide where they don't find." [He had a 'secret' that Christina also knew about - a radioactive explosive missing or stolen from the Los Alamos, New Mexico Nuclear Test Site.]

When he returns to Lily's apartment, Hammer finds her frightened and hiding on a lower stairwell: "They came last night right after you left. I heard them. I hid in the basement...Look, I've gotta get out of here." He gives her a signal with his car's horn honk to "come running." The camera is positioned high above her as she begins to descend the long staircase - then, it reverses its position and shoots from a low-angle at the foot of the stairs as she rushes down toward his car to be taken to his apartment.

As Nick does repairs under a car, an unseen man - with blue suede shoes - ominously approaches and releases the air pressure in the jack. The car crushes Nick to death under its weight as the hydraulic jack cranes down. The camera dynamically follows the car down as it kills him.

In Hammer's apartment, Lily throws herself at him, thankfully embraces and kisses him. Coldly, he steps back from her: "OK, you've made your point. You're welcome." Then, as he leaves, she assumes the posture of a helpless waif needing his protection. After discovering Nick's death, and being told by a mournful Sammy (Jerry Zinneman), Nick's mechanic/assistant: "No more va-va-voom," Mike visits Velda's apartment, where he finds her in bed. Gratefully, she senses that he is in trouble and might need her, but is frustrated about his deadly, spiritually-empty quest and vengeful, greedy desires that are slowly killing all his friends. She also speaks about "the nameless ones who kill people for the great whatzit":

Velda: I'm always glad when you're in trouble because then you always come to me. What is it, Mike?
Hammer: Nick's dead...The jack slipped and the car came down on him.
Velda: Is that what really happened?
Hammer: He was doing a couple of jobs for me.
Velda: And he got it? Mike, all your friends are gonna get it one of these days. What is it you're after, Mike?
Hammer: Something Nicholas Raymondo had and the girl knew about. Something very valuable.
Velda: Is it worth Nick's life or, or Christina's or Raymondo's or Kawolsky's or mine?
Hammer: Or Lily Carver's, Christina's roommate? She's up in my apartment. They tried to get her last night.
Velda: They? A wonderful word. And who are they? They're the nameless ones who kill people for the great whatzit. Does it exist? Who cares? Everyone everywhere is so involved in the fruitless search for what? Why don't you turn her over to Pat? It's his job to protect her, if she needs protection. Or to question her if that's what's needed. Why are you always tryin' to make a noise like a cop?
Hammer: What are you doing in bed so early?
Velda: Oh, I had a few drinks. I'm trying to sleep off a hang-over.

Velda has another name and lead from Ray Diker - "a dealer in abstract art or something...He dropped a few names. Want to hear them?" As Hammer calmly drinks milk on her sofa, she desperately tries to pique his sexual interest in all of her sacrificial 'dirty work' that she has masochistically done for him to help his case (she has pimped and prostituted herself with the art dealer, and will do the same with Dr. Soberin):

Velda: Carl Evello you know, but Dr. Soberin. Does that do anything for you? This joker says there's new art in the world and this doctor's starting a collection...He tried to date me. With a few drinks and one thing leading to another, I suppose I could get some more information about the doctor. Do you want me to date him? Well?...Well, what do ya think?
Hammer: I think I'd like to get my hands on whoever killed Nick.
Velda: You want to avenge the death of your dear friend. How touching. How sweet. How nicely it justifies your quest for the great whatzit. Why don't you leave, Mike, before I change my mind? Besides, I'm gonna need all the rest I can get if I'm gonna have any strength to fight off my new found and my bosom friend.

At a local black nightclub where he has arranged to meet Velda - a place where a black blues singer (Madi Comfort) entertains with the film's theme song: Rather Have the Blues, Hammer is "wasted" and has no energy to respond to the black bartender's salute to their deceased friend: "Va-va-voom. Pretty pow!" Falling drunk on the bar, Mike is later told by the bartender that his girl, Velda, has been kidnapped [while on her way, against her wishes, to a date with Dr. Soberin through her art dealer contact] and is now in harm's way: "A fella just come in. Said they got your girl. They've got Velda. Told me to tell ya."

To retrace his steps and rescue his faithful Velda, Hammer returns to the gas station where Christina asked the attendant to post a letter. He asks: "Do you happen to know who it was addressed to?" To his consternation, he is told: "It was addressed to some joker named Mike." Christina addressed the letter to him!, using the address on the steering column's registration. He races home and into his darkened office where he finds the opened letter in a stack of envelopes on his desk. The message in the letter simply reads: "Remember Me!" Evello's two hoods in the shadows, who have already read the letter, hold a gun on him and knock him out with a blackjack.

Hammer is abducted and brought to a beach house [belonging to Dr. Soberin]. After a brief scuffle on the sand and in the ocean as Hammer attempts a futile escape [an ironic foreshadowing of another unsuccessful escape at the film's end], he is beaten up, dragged inside and tied and bound by ropes in an X-posture face-down on a bed. The man with the blue suede shoes, Dr. Soberin (Albert Dekker), a trafficker in atomic material, philosophically advises him to remember - it is the same smooth, melodious, soft-spoken voice that was present when Christina was tortured to death:

Lie still. Why torment yourself? Who would you see? Someone you do not know, a stranger. What is it we are seeking? Diamonds, rubies, gold? Perhaps narcotics? How civilized this earth used to be. But as the world becomes more primitive, its treasures become more fabulous. Perhaps sentiment will succeed where greed failed. You will die, Mr. Hammer. But your friend, you can save her. Yes you can. The young lady you picked up on the highway. She wrote you a letter. In it were two words: 'Remember Me.' She asks you to remember. What is it you must remember?

Hammer's pants leg is pulled up and he is injected with a hypodermic needle full of sodium pentothal - a truth serum - to stimulate his memories while sleeping: "And while you sleep, your subconscious will provide the answer. And you will cry out what it is that you must remember. Pleasant dreams, Mr. Hammer." With false affection resembling the bedside manner of a true doctor, Dr. Soberin pats Hammer's leg after administering the dose. Hammer's ramblings during sleep are, however, incomprehensible to both Evello and to the chief villain - the man with the blue suede shoes. Hammer maneuvers his hands out of the ropes, pretends that he is restrained, knocks out Evello as he 'talks,' and ties up Evello in his place on the bed. Sugar, who has been listening to a boxing match on the radio with Charlie, is summoned into the bedroom and tricked into knifing Evello in the back with a switchblade. After applying more judo moves on Sugar off-screen (and killing him?), Hammer escapes through the bedroom window and steals a car from the driveway. [All during this scene, the boxing match is heard on the soundtrack - the one that Yeager said he wouldn't have his fighter suddenly lose.]

Back in his apartment where Lily has now dressed up in sexy clothes and wears perfume brought earlier by Velda, Hammer tries to decipher the mantra-like phrase: "Remember Me." Detached and averse to cultured poetry, he asks Lily to read the cryptic love sonnet Remember from the book of poems by Christina Rossetti:

Remember me when no more day by day
You tell me of a future which you plan
Only remember me, you'll understand
But if the darkness and corruption leave
A vestige of the thoughts that once we had.

By decoding the poem, Mike assumes that the 'vestige' referred to is something that Christina hid on herself before being captured when he first met her. At the morgue, the elderly, rat-faced coroner Dr. Kennedy (Percy Helton) pulls out the drawer containing Christina's body. With the camera positioned inside the morgue drawer - from the corpse's point-of-view - Hammer muses about "something small, something she could hide, but where would she hide it? She didn't have time at the gas station. She swallowed it. (To the nodding coroner) And if she swallowed it, you've got it." In his office, the mercenary, corrupt coroner reaches for a drawer and removes the key that he had found in Christina's stomach during the autopsy, extending his other hand for a pay-off. [Factual Error (possibly): Could you autopsy an incinerated body inside a vehicle and find a key in the deceased's stomach?] When Hammer refuses to peel off any more bills, the greedy coroner replaces the key in the drawer - Hammer violently slams the drawer shut and crushes the man's hand. The man screams as Hammer grins sadistically at his pain. Eventually, he releases the drawer and the man whimpers as he falls to the floor.

The key is labeled: "H.A.C." for the Hollywood Athletic Club - Hammer's next destination. After being slapped around, the defenseless old desk attendant (Keith McConnell) in the club identifies the key as Nicholas Raymondo's locker key, part of his ten year membership. Hammer is led to the locker room where the locker is opened and the 'great whatzit' is found - it is a leather-bound and strapped case sitting at the bottom of the gym locker. Inside the leather case is another heavier, metal-lined case, hot to the touch. As he opens the case, a blinding-bright, luminous light emanates from within, and seers a burn across his right wrist. He replaces the leather top and tells the bewildered attendant: "Whatever it is, keep away. Don't let anybody near." When he returns to his car, Lily has disappeared.

At his home, Hammer finds the police waiting for him, demanding the key. At the mention of Lily Carver's name, a disgusted Murphy tells Hammer that things are over his head and that Lily is really an imposter (and possible murderess of Christina's roommate):

We fished Carver's body out of the harbor over a week ago. You're so bright working on your own, you penny-ante gumshoe. You thought you saw something big and you tried to horn in. What about this dame who's passing herself off as Carver?

When he reaches for a cigarette, Murphy notices the radioactive burn across Hammer's wrist - he asks, and warns about the atomic isotope that was stolen from the top-secret Los Alamos New Mexico Nuclear Test Site:

Where'd ya get that? Now listen, Mike. Listen carefully. I'm going to pronounce a few words. They're harmless words. Just a bunch of letters scrambled together. But their meaning is very important. Try to understand what they mean. 'Manhattan Project, Los Alamos, Trinity.'

Feeling duly chastened and warned about the box's destructive power, Hammer turns over the key, and then requests help in freeing Velda. The police official is vindictive and uncooperative with Hammer's meandering, indiscriminate, and hurtful independence as a gumshoe:

Murphy: Let the big slob sit there and think about his girl. What's likely to happen to her?
Hammer: I didn't know.
Murphy: You didn't know. Do you think you'd have done any different if you had known?

Hammer telephones the Hollywood Athletic Club but there is no answer. The phone rings unanswered as the camera pans down the broken-open, empty locker, with the attendant lying dead on the floor next to it.

Now anxious to save his girl, Hammer beats up and slaps Ray Diker and discovers the name of the art dealer: "The man you pointed out to Velda - what's his name?" After being told the man's name is William Mist, Hammer breaks into Mist's Gallery of Modern Art, strides on a marble floor past magnificent paintings, and finds the terrified art dealer swallowing a whole bottle of sleeping pills. After manhandling Mist - now in a drugged stupor and unable to answer questions about Velda's whereabouts, Hammer switches on the man's radio - which is coincidentally tuned to a classical music station playing Chopin's Revolutionary Etude. He reads Dr. G. E. Soberin's name [with initials alluding to the General Electric Corporation] off the prescription label on the pill container.

Recollecting what Velda told him about Soberin (Velda's echoing voice rings in his ears: "...He dropped a few names. Does that make your ears stand up? Want to hear them? Dr. Soberin. Does that do anything for ya? Dr. Soberin. Does that do anything for ya?"), he phones Soberin's office, and the answering service suggests reaching the doctor at his secluded "beach cottage," although there is no phone there. Hammer concludes that the beachhouse is the same one where he was held captive.

In the isolated beach house, the camera pans up from blue suede shoes to the face of Dr. Soberin - he holds a gun in his hands and wearily tells Lily, his confederate and lover/companion, about his going-away plans to a place where he can be "sad and melancholy again" - without her:

There is something sad and melancholy about trips. I always hate to go away. But one has to find some new place or it would be impossible to be sad and melancholy again.

The neurotic doctor's moll strokes the box, insatiably curious and asking about its contents, but the urbane doctor only patronizes her with confusing, mythological, metaphysical allusions. [Her real name is Gabrielle - the feminine variant of Dante Rosetti's middle name.]:

Dr. Soberin: Curiosity killed a cat and it certainly would have you if you'd followed your impulse to open it. You did very well to call me when you did.
Lily: Yes, I know. But what's in it?
Dr. Soberin: You have been misnamed, Gabrielle. You should have been called Pandora. She had a curiosity about a box and opened it and let loose all the evil in the world.
Lily: Never mind about the evil. What's in it?
Dr. Soberin: Did you ever hear of Lot's wife?
Lily: No.
Dr. Soberin: No. Well, she was told not to look back. But she disobeyed and she was changed into a pillar of salt.
Lily: Well, I just want to know what it is.
Dr. Soberin: Would you believe me if I told you? Would you be satisfied?
Lily: Maybe.
Dr. Soberin: The head of the Medusa. That's what's in the box. And whoever looks on her will be changed, not into stone, but into brimstone and ashes. Well, of course, you wouldn't believe me. You'd have to see for yourself, wouldn't you?
Lily: Where are we going?
Dr. Soberin: Where I am going, it is not possible for you to go. I had no illusion about deceiving you. You have the feline perceptions that all women have...
Lily: Whatever is in that box - it must be very precious. So many people have died for it.
Dr. Soberin: Yes, it is very precious.
Lily: I want half.
Dr. Soberin: I agree with you. You should have at least half. You deserve it, for all the creature comforts you've given me. But unfortunately, the object in this box cannot be divided.
Lily: (She points a gun at him) Then I'll take it all (pause) if you don't mind.

[The leather-bound box predates the glowing briefcase in Quentin Tarantino's Pulp Fiction (1994).] When she feels betrayed for being ditched and for not being promised her rightful half of the proceeds from the theft and attempted sale of the 'whatzit' (fissionable material), she shoots and wounds the deceitful doctor. As he slowly wavers and dies while standing in front of her after underestimating her lethal, uncontrollable greed, he warns with archaic allusions:

Listen to me, as if I were Cerberus barking with all his heads at the gates of Hell, I will tell you where to take it. But don't, don't open the box.

After collapsing, Hammer bursts into the room looking for Velda as an avaricious and determined Lily begins to open the treasured box. She greets him with a wide smile and a gun: "Hello, Mike. Come in. Come in." Seductively, she commands sexual favors from him:

Kiss me, Mike. I want you to kiss me. Kiss me. The liar's kiss that says 'I love you.' It means something else. You're good at giving such kisses. Kiss me.

With the femme fatale's destructive sexuality and promise of the kiss of death, she fires point-blank into the midsection of the misogynistic hero before he reaches her, and he falls to the floor - wounded. Still brutish and uncomprehending in his own sleuthing case's techniques, Hammer fails to admonish the completely naive Lily about the danger of opening up her case.

In the film's amazing finale [in a scene reminiscent of the climax of Raiders of the Lost Ark (1981), and similar to the Biblical tale of Lot's wife who failed to heed warnings], the modern-day Pandora lifts the leather top from the case, and then touches the lid, feeling the heat with her caress. But undeterred, disobedient and ignorant, she raises the lid in a quest for knowledge of what's contained within - a hissing, hellish, unearthly noise emanates from the interior of the box as the searing light hits her face. She pursues her perverse fascination with the fiery light by lifting the lid even higher. As she unleashes the apocalyptic forces inside and the box cannot be closed, she becomes a flaring pillar of fire as it consumes her. As the destructive, white-hot, evil forces are freed, she becomes a shrieking, human torch.

Revived, Hammer stirs on the floor, witnesses Lily's horrible death, and crawls toward the room where a half-clothed Velda is imprisoned in a locked room. Freeing her, they scramble in each other's arms and escape from the beach house toward the sand and water. The house is soon engulfed with a wave of flashes, fireballs, and series of mushroom-cloud explosions, as nuclear conflagration approaches. [The 'darkness and corruption' described in the Christina love sonnet have come to fruition.] The couple looks back at the imploding house as they escape down the beach and cower together, while trying to cool off in the surf. As they hug waist-deep in the foaming waves of the ocean, THE END appears on top of them. [The ending of this film anticipated the universal-annihilation finale of Stanley Kubrick's Dr. Strangelove (1964).]

In an alternative, shorter ending - another version of the film, Velda and Hammer never make it to the beach - there is nuclear annihilation. The house explodes in successive, chain-reaction waves of apocalyptic light and heat.

The final words THE END zoom out from the inside of the house.