The film opens with a bleak shot of mountain peaks sticking up above a sea of clouds, as a narrator explains the rumors that the Soviet Union had been working on a doomsday device. We presume these to be the peaks of the Zhokhov islands, which the narrator mentions as the location of the doomsday project. The film then cuts to the credit sequence, shown over a montage of a USAF B-52 engaged in a mid-air refuel while “Try a Little Tenderness” plays.
At Burpleson Air Force Base, Group Captain Lionel Mandrake is summoned to the phone to take a call from General Jack D. Ripper, the base commander. Ripper issues instructions to Mandrake to put the base under condition red, seal the base, and impound all radios. He impresses upon Mandrake the seriousness and importance of the situation, telling him that a shooting war has begun, and has Mandrake transmit “attack Plan R” to the 843rd bomb wing, which the base commands.
Over a montage of a B-52 bombers in flight with escorts, the narrator explains Operation Dropkick, in which the US Strategic Air Command maintains a force of bombers airborne 24 hours a day, armed with nuclear payloads. We are then shown the interior of a USAF B-52, where Major T.J. “King” Kong and his team are bored, snacking, reading Playboy, and playing cards. Suddenly a radio transmitter springs to life and delivers a code that the communicator decodes as Wing Attack Plan R. Nobody on board believes it, and Major Kong comes back to the radio himself to double check the code. They assume it means that the Soviets have already attacked Washington D.C., and they are being ordered to retaliate. Major Kong delivers a speech about the gravity and importance of nuclear combat, and the crew begins preparations for Attack Plan R.
A telephone rings in the bedroom of General Buck Turgidson, USAF Chief of Staff, and his secretary and mistress, Miss Scott, who is tanning on the bed under a light and in a bikini, answers the phone. A conversation between Turgidson and the Colonel on the other end of the line ensues, with Miss Scott as the middleman, shouting information across the room so Turgidson can hear. Turgidson is told that Ripper issued Attack Plan R to his wing, and cut off all communication with the outside world, despite there being no credible threat to the US. Back at Burpleson, Ripper and his soldiers prepare to defend the base from attack; only Ripper knows that it will be US soldiers attacking. Mandrake switches on a radio and hears civilian broadcasting, indicating that there is not actually a shooting war going on between the US and Soviet Union. On the bomber, Major Kong and his crew switch on the radio discriminator, which prevents any communications from being received unless they are preceded by a three-letter code prefix, which we are shown is “O-P-E,” but which only Ripper knows back on the ground.
The film proceeds to switch between three settings: the B-52 bomber, Burpleson Air Force Base, and the War Room at the Pentagon in Washington DC. Only the audience knows what is happening in these three discrete locations, because the characters are unable to communicate with the people in one of the other settings due to the sealing of Burpleson and the radio discriminator on the bomber. At Burpleson, Captain Mandrake excitedly plays the radio for Ripper, telling him he can recall the planes because there must be a mistake, and not realizing yet that Ripper has lost his mind and issued the attack himself. Ripper scolds Mandrake, then locks them in his office together, threatens Mandrake with a gun when Mandrake demands the recall code, and explains his plan to force the US government into supporting the rogue bomber wing and issuing an attack on the Soviet Union. Mandrake begins to realize that Ripper has gone insane, as Ripper explains his belief that there is a communist conspiracy to “impurify our precious bodily fluids.”
In the War Room, US President Merkin Muffley learns about the unfolding situation from a defensive, haughty, self-important General Turgidson. Turgidson is slow to give the President every detail and reveal the fault of the USAF in the crisis, and the President grows more and more angry with him, and the two bicker back and forth. The President orders a nearby army unit to attack Burpleson and establish contact with Ripper, and Turgidson urges him to instead support the rogue bomber wing and issue an all out attack on the Soviet Union, in order to sufficiently weaken them to prevent a full retaliation. The Russian ambassador Alexiy de Sadesky is invited to the War Room to negotiate, and Turgidson is livid that a foreigner would be allowed into this top secret space. Turgidson and the ambassador bicker and eventually physically fight before the President gets the Soviet Premier on the phone and the ambassador finally helps negotiate. Meanwhile, the bomber continues to ready itself for the attack.
At Burpleson, the attack by the US Army unit begins and the soldiers at Burpleson think the Soviets have disguised themselves as Americans because of what Ripper told them. A firefight breaks out, and Ripper, still holding Mandrake captive in his office, explains that he believes the fluoridation of water in the US is an international communist conspiracy. Gunfire bursts through the office window, and Ripper pulls a massive machine gun out of his golf bag, gets ready to return fire, and makes Mandrake feed him the ammunition belt. Over the course of the gunfight, Ripper continues to explain his theory, remains incredibly calm in the face of flying bullets and glass, and eventually reveals that he developed his theory about fluoridation after he diagnosed a decline in sexual prowess as a problem caused by “loss of essence.”
Meanwhile, in the War Room, the ambassador tries to help President Muffley communicate with the Soviet Premier, who is with a mistress and so drunk that the President must speak to him like a child. The Premier explains to the ambassador that work on the Soviet Doomsday Machine is completed and the machine is armed, which de Sadeski relays to the President and the rest of the War Room. Turgidson is in disbelief, and thinks that de Sadesky is lying to make the Americans work harder to get the planes back. De Sadesky explains the discovery of “Cobalt Thorium G,” which has a radioactive half-life of 93 years. De Sadesky tells them that the Doomsday Machine is connected to a network of computers that will unleash the bomb if a nuclear weapon is detonated in the Soviet Union, and that it is designed to explode if any attempt is made to disarm it. He explains that it was the cheapest way to ensure deterrence by mutually assured destruction, and that the Soviet Union only went through with it when they found out that the US was working on something similar.
At this moment Dr. Strangelove, the title character, is introduced for the first time. He is wheelchair bound, has a black glove on one hand, and is a stereotypical mad scientist (dressed grimly, wild white hair). He has a heavy German or Austrian accent. He explains that he did commission a study of such a project, but determined it was not practical as a deterrent, though it is relatively easy to pull off. Strangelove explains some of the technology and theory behind such a weapon, and criticizes the Russians for not telling the world about the Doomsday Machine, which makes it useless as a deterrent. De Sadesky explains that it was to be announced soon, as a surprise, because the Soviet Premier loves surprises.
Eventually, the Burpleson soldiers surrender to the army unit. Mandrake continues to try to convince Ripper to give him the codes. Ripper realizes that his men have surrendered, and dejected, drops his own weapon. Ripper admits he does not think he would hold up well under torture, and goes into the bathroom to commit suicide. Mandrake does not realize what Ripper is doing, and is caught off guard by the suicide, having never learned the recall code. The bomber is hit by a missile and suffers serious damage but the crew recovers and his able to continue flying. The next time it cuts back to them, we find out that the radio is badly damaged and they are leaking fuel but they should still be able to make it to their primary target.
At the base, Mandrake frantically searches through Ripper’s notes, and finds a piece of paper scribbled with “Peace on Earth” and “Purity of Essence,” and realizes the code must be some variation of “P-O-E.” Suddenly, the door is shot open and Colonel “Bat” Guano enters, brandishing an M1 carbine. He is immediately suspicious of Mandrake because he is not an American, and thinks that Mandrake killed Ripper. Mandrake, now the acting head of command at Burpelson, has a difficult time convincing Col. Guano that he needs to reach Strategic Air Command. Col. Guano starts marching Mandrake out of the office at gunpoint. Col. Guano thinks that Mandrake killed Ripper in some conspiracy to hide his own “perversions.” Col. Guano finally lets Mandrake try to get in touch with the President, but Mandrake is hindered by a payphone and an operator who refuses to put him through without the correct amount of change. Mandrake asks Col. Guano to shoot the lock off of the Coca-Cola machine so that they can use the change for a payphone. Col. Guano is incredibly protective of the machine, which he does not want to steal from because it is “private property,” but he finally capitulates and is sprayed in the face with soda as he bends to recover the change.
In the War Room, we find out that the recall code O-P-E has been received and acknowledged. Everyone in the room starts celebrating. We hear that 4 planes are reported destroyed by the enemy, and the other 30 planes are turning around. Just before it cuts away again, we find out that the Soviet Premier is on the phone again, and very upset about something. It turns out that three planes were destroyed, and the fourth, which we know to be Major Kong’s plane, was only damaged and is still headed for its target. The President encourages the Soviet Premier to shoot down the plane, and focus all of his defenses on the bomber’s primary and secondary targets at Laputa and Bordkov. The President asks Turgidson if the plane could really make it through all the Soviet defenses, and Turgidson forgets the gravity of the situation and gets excited while explaining that a good enough pilot could certainly make it through and drop the bomb.
In a series of scenes that interrupt those in the War Room, we find out that fuel leakage on the bomber has increased. The navigator tells Major Kong that with the new rate of fuel loss, they will never make it to their primary target at Laputa. Major Kong is still determined to drop the payload. The crew redirects to a new target, an ICBM complex at Kodlosk. As the bomber approaches its new target, the bomb doors will not open because of the damage to the plane. Major Kong goes down to the bomb compartment to manually open the doors himself. The doors open and Major Kong grabs his hat to keep it from flying off as the bomb is released. Major Kong rides the bomb in its falling arc, waving his hat over his head like a rodeo star and yahoo-ing. The bomb reaches the ground and detonates.
In the War Room, Dr. Strangelove immediately begins advising a network of mine shafts for the survival of a small population. The rest of the people in the War Room get on board with the plan, quickly abandoning any attempt to prevent the unfolding nuclear situation. Led by Muffley, they question Strangelove about his plan, which involves the assurance that everyone in the room would survive and that they would need to reproduce prodigiously, so there would be a ratio of 10 women to each man. Throughout the scene, Strangelove struggles to control his alien hand, which keeps on trying to do a Nazi salute or strangle him. Turgidson and another general worry that the Russians will overcome the Americans with superior mine shaft technology, and warn of a “mine shaft gap.” Strangelove stands up from his wheelchair excitedly, announcing that he has a plan before he realizes that he has stood. The scene ends with Strangelove’s exclamation, “mein fuhrer, I can walk!” A one and a half minute long montage of nuclear bombs exploding closes the film, with the song “We’ll Meet Again,” by Vera Lynn playing over it.