Soon, a shadowy hand appears from behind the darkened bedroom door holding a silencer, and six shots are fired into the bundle of pillows and sheets. The gun hand belongs to Professor Dent. Bond forces Dent to drop his gun and while they talk, Dent tries to distract Bond while edging his gun closer and closer on the floor rug. When Dent finally retrieves and seizes his pistol, he fires it at Bond, but it only clicks empty. Bond points his own Walther PPK gun at Dent and menaces him with a classic line, shooting him down in cold blood, and then blowing on the end of the gun's barrel:

That's a Smith and Wesson. And you've had your six.

Arriving two hours late at the Kingston Harbor, Bond sets off at night with Quarrel and Leiter to Crab Key Island, to investigate the island where Strangways had collected radioactive rock samples. With a plan to rejoin Leiter in a motorboat in about twelve hours, Quarrel and Bond take off in a sailing/rowboat, arriving in the middle of the night. They hide their boat and then spend the remaining early morning hours resting in the jungle until the sun rises.

In the film's most unforgettable sequence, Bond awakens to the sound of a girl's voice singing "Underneath the Mango Tree." And then on the beach rising Venus-like from the water with giant seashells, Bond has his first view of Honey Ryder (Ursula Andress), an innocent, voluptuous island girl/diver wearing a sexy, white bikini and hunting knife. [Halle Berry would recreate this famous scene as Jinx Johnson in a bright orange bikini in the Bond film, Die Another Day (2002).] His own appearance from the undergrowth startles her:

Honey: Who's that?
Bond: It's all right. I'm not supposed to be here either. I take it you're not. Are you alone?
Honey: What are you doing here? Looking for shells?
Bond (glibly): No, I'm just looking.
Honey: Stay where you are.
Bond: I promise I won't steal your shells.
Honey: I promise you you won't either. Stay where you are! (She draws her hunting knife and threatens him)
Bond: I can assure you my intentions are strictly honorable.

Honey appears carefree and unafraid of discovery, often visiting the island to collect shells: "At first, they used to try to catch me, but they couldn't. Now, I don't think they bother anymore." Bond warns that it will be different this time: "Well, they will this time."

A high-powered motorboat roars along the beach, and they rush to take cover. It sprays the entire area with machine gun fire, then leaves after warning to return with dogs. Both Honey and Quarrel are fearful, especially of the island's dragon: "He had two great glaring eyes, short tail and pointed wings, and was breathing fire." Honey's boat is found to be shot full of holes, making it impossible for her to leave the island without them.

As they make their way across the island, Honey, like a female Tarzan, guides them and teaches them how to be evasive. By breathing through reeds from underwater, the three escape capture and detection by guard dogs. One lone guard with a machine gun is knifed in the back by Bond, as Honey expresses her horror: "Why?" Bond replies: "Because I had to". Quarrel discovers the tire tracks of the "dragon" which haunts Crab Key.

During the day while they hide, Honey tells Bond about herself. She was the only child of a marine zoologist, who studied seashells throughout the world (the Philippines, Bali, Hawaii, "just about anywhere there were shells"). Although her father was reported drowned at Crab Key, Honey believes that he was "far too good a diver for that to happen to him." He was probably murdered by Dr. No and his henchman and she was made an orphan. For schooling, she has been reading an encyclopedia since childhood: "I started at A when I was eight and now I've reached T." "I'll bet I know a lot more things than you do," she boasts.

After her father's death, she stayed on a while in Kingston, until her kindly benefactor turned on her and she sought revenge: "I scratched his face, and then..., but he was stronger than I was...I put a black widow spider underneath his mosquito net. A female, and they're the worst. It took him a whole week to die." Bond finds her story unsettling: "Well, it wouldn't do to make a habit of it."

Later that evening on the beach, they are confronted by the "dragon," but Bond tells Quarrel not to worry: "A dragon that runs on diesel engines. You can forget the spooks, Quarrel." In a battle with the dragon, an amphibious, diesel-engined swamp vehicle (disguised as a dragon to scare the locals), Quarrel is burned to death, incinerated by the flame thrower, as Bond fires vainly at the glaring headlights of the camouflaged tank. In a hopeless situation on the sand flats, Bond and Honey surrender and are captured by guards wearing fire-protective suits. When a hand-cuffed Bond resists after one of the guards pushes Honey, they are both beaten and bruised.

First, they are taken to Dr. No's radioactive-decontamination chamber, where they are sprayed with a white foamy substance and then given a short rub-down with a long-handled broom. When the levels of radiation are still too high, they are ordered to take off all their clothes. Bond amusingly attempts to order his own captors about:

Bond: Do the girl first.
Captor: Now look man. We give the orders around here.
Bond: Yeah, that's fine, but do something about this, will ya? (gesturing toward his handcuffs)

The guards oblige him. They are put naked onto a conveyor belt through a series of showers, to further reduce the dangerous radioactive levels on their bodies. Lighted signs before each shower spray indicate the decreasing level of contamination as they pass down the conveyor belt. Finally, garbed in light blue towels, they are ushered into a bank vault-like door set in a rock, where they are welcomed by two Chinese women dressed in white, Sister Rose (Michele Mok) and Sister Lily (Yvonne Shima):

Sister Lily: Come in, you poor dears. We simply didn't know when to expect you. First it was teatime yesterday, and then dinner and it was only half an hour ago we really knew you were on your way.
Sister Rose: Cigarette? These are American, there's English, and there's Turkish...We hope to make your stay as pleasant as possible.
Bond: That's really most kind of you. But for the moment...
Sister Lily: Of course, you'll be wanting to see your room. Breakfast is already ordered, and then you'll want to sleep. The Dr. left strict orders. You're not to be disturbed until this evening. He'll be delighted if you'll join him for dinner.

The two captives are shown their luxurious quarters (equipped with properly-sized clothing for each of them) by Sister Lily:

Sister Lily: Don't hesitate to ring if there's anything else you want. Anything at all.
Bond: Such as two air tickets to London?
Sister Lily (politely ignoring him): I'll leave you two dear people in peace.

While unknowingly drinking the drugged coffee on the breakfast tray in their rooms, they realize that they are imprisoned: "Mink lined, with first-class service." Both of them quickly pass out from the effects of the coffee. After they have been put into their beds in an unconscious state for a drugged sleep, the door slides open - only a pair of white shoes and starchly-pressed white trousers are seen stepping inside and walking over to Bond's bed. A plastic, black metallic-like hand reaches down and pulls back the sheet from under Bond's face. The mysterious figure [of Dr. No] gazes at his victim for a moment, and then leaves as silently as he approached.

After awakening and recovering, Bond and Honey dress for dinner and then are led to an elevator which takes them into the depths of Dr. No's underground lair. They emerge into a decorated living room a la Captain Nemo, one wall of which is an observation panel - a large piece of glass through which they see a perfect view of the undersea world.

The scene of the confrontation between Bond and Dr. No in his Crab Key Island fortress is a classic one. Bond's thoughts are interrupted by a voice behind him:

Bond: Artificial light. We could be hundreds of feet beneath the sea here.
Honey: And look at that. Sea turtles! They do not grow above two hundred feet.
Dr. No: One million dollars, Mr. Bond. (They turn and see Dr. No for the first time) You were wondering what it cost.
Bond: As a matter of fact, I was.

Bond's ruthless arch-enemy, Dr. No (Joseph Wiseman) appears in a plain white Nehru jacket with a pair of shiny black, plastic hands, the result of a "misfortune." He continues to describe the aquarium, while Bond persists in provoking him:

Dr. No: A unique feat of engineering if I may say so. I designed it myself. The glass is convex, ten inches thick, which accounts for the magnifying effect.
Bond (retorting): Minnow pretending they're whales. Just like you on this island, Dr. No.
Dr. No (countering): It depends, Mr. Bond, on which side the glass you are.

Bond is offered a drink on a tray by a servant - a famous second instance of Bond's particular drink preference:

Dr. No: A medium dry Martini, lemon peel, shaken not stirred.
Bond: Vodka?
Dr. No: Of course.

During dinner, Dr. No explains his background when he was in the Tong Society (a Chinese version of the Mafia), with a cold, calculating, and precise manner:

Dr. No: I was the unwanted child of a German missionary and a Chinese girl of good family. Yet I became treasurer of the most powerful criminal society in China.
Bond: It's rare for the Tongs to trust anyone who isn't completely Chinese.
Dr. No: I doubt they should do so again. I escaped to America with $10 million of their dollars in gold.
Bond: That's how you financed this operation. It was a good idea to use atomic power. I'm glad to see you can handle it properly...
Dr. No: My work has given me a unique knowledge of radioactivity. But not without costs, as you see.

Dr. No shows some respect for Bond: "I only gratify your curiosity because you're the one man I met capable of appreciating what I've done. And keeping it to himself." When Dr. No orders Honey to be dragged from the room ("I'm sure the guards will amuse her,") Bond tries to help her by grabbing a bottle as a weapon, but he is restrained by a guard:

Dr. No: That's a Dom Perignon '55. It would be a pity to break it.
Bond: I prefer the '53 myself.

Bond continues to provoke Dr. No by referring to his evil, blackmailing plan for world domination by deflecting and altering the flight paths of Cape Canaveral's nuclear rocket launches towards the US itself:

Does the toppling of American missiles really compensate for having no hands?

Dr. No describes how he was rejected by both Eastern and Western countries and their scientific communities, and is now a leading agent for S.P.E.C.T.R.E. (a criminal organization acronym):

Dr. No: East. West. Just points of the compass. Each as stupid as the other. I'm a member of S.P.E.C.T.R.E....Special Executive for Counterintelligence, Terrorism, Revenge, Extortion. The four great cornerstones of power headed by the greatest brains in the world.
Bond: Correction. Criminal brains.
Dr. No: A successful criminal brain is always superior. It has to be.
Bond: Why become criminal? I'm sure the West would welcome a scientist of your calibre.
Dr. No: The Americans are fools. I offered my services. They refused. So did the East. Now they can both pay for their mistake.
Bond: World domination. Same old dream. Our asylums are full of people who think they're Napoleon or God.
Dr. No: You persist in trying to provoke me, Mr. Bond. I could have had you killed in the swamp.
Bond: And why didn't you?
Dr. No: I thought you less stupid. Usually when a man gets in my way (he picks up a gold ornament from the table and crushes it with his metal hand), but you are different. You cost me time, money, effort. You damage my organization and my pride. I was curious to see what kind of a man you were. I thought there might even be a place for you with SPECTRE.
Bond: Well, I'm flattered. I'd prefer the Revenge Department. Of course, my first job would be finding the man who killed Strangways and Quarrel.
Dr. No: Unfortunately, I misjudged you. You are just a stupid policeman whose luck has run out.

After Bond refuses to work for SPECTRE and tension has increased to intolerable levels between them, Dr. No is not amused by Bond and asserts:

I never fail, Mr. Bond.

He orders his guard to "soften him up. I haven't finished with him yet," and then leaves for the control room to prepare for another "toppling" of a US rocket guidance system with a nuclear-powered radio beam.

Bond regains consciousness in a smaller, less-luxurious prison cell, where he wakes up on a bunk bed. After climbing up to a small electrified ventilation grill at the top of one wall, he is thrown backwards when shocked. But he tries again - this time using his shoe to knock out the grill. He successfully escapes his jail cell by crawling through the grill into the super-heated ventilation shaft of the conditioning system.

In the shaft, Bond is hit by a flood of water projected through the narrow tunnel, and barely survives being drowned. He makes his way to another ventilation grill, kicks it out, drops down into another room, and there overpowers one of Dr. No's technicians. With the disguise of the man's radiation suit, Bond makes his way into Dr. No's laboratory control room, where an atomic reactor is shielded in a pool of water.

The countdown toward the Cape Canaveral rocket launch has begun, viewed on TV screens in the control room. Bond is assigned to the metal catwalk above the reactor, where he makes an attempt to destroy the nuclear reactor and abort Dr. No's sabotage of the launch. He turns a wheel on the reactor's control panel, sending the radiation indicator up beyond the danger level to a point of no-return. Flashing signs and lights indicate serious damage. The reactor attendant notices what has happened and tries to stop Bond, but is knocked from the catwalk.

Red "Abandon Area" lights flash as the staff scurries and flees from the control room. The arch-villain Dr. No runs in a mechanically-stiff stride toward Bond on the catwalk, and ends up battling him on the descending gantry which is moving down into the furiously boiling pool of water containing the reactor.

In the exciting fight to the finish in mortal hand-to-hand combat over the reactor pool, Bond manages to climb up to safety, but as Dr. No desperately clutches at the steel supports of the platform, his metallic, artificial hands cannot get a grip on the steel legs of the sinking gantry. He is submerged into the bubbling water of the reactor, sinking into the steaming, boiling mixture. Meanwhile, the US rocket is successfully launched, but the entire island complex approaches toward a major meltdown.

Rushing from the deserted control room, Bond searches for Honey, and discovers her in a room where she is chained hand and foot to a slanted, concrete floor, threatened by water rushing at her from a sluice gate. Bond cuts her free and they both race toward a motorboat. As they escape out into the water, the reactor reaches critical mass, and Dr. No's complex is blown to pieces in a shattering explosion.

Their motorboat drifts aimlessly after running out of fuel: "Well," says castaway Bond to Honey, "we can swim or, uh...come here." With a detachment of Marines on a boat, Felix Leiter approaches to rescue Bond, and they are given a tow. During a passionate kiss and embrace, Bond decides he doesn't want to be rescued, and he releases the tow line - they are adrift once again.