In a Middle Eastern country, Barney and Willy pose as soldiers and break into Interoco, a chemical manufacturing plant. They go to a vault where Dehominant-A, a lethal gas, is stored and move the canisters out of the way so that they can get to the computer on the other side of one wall. Willy unwittingly knocks one canister open. Barney inadvertently steps in the leaking chemical and his leg is instantly paralyzed.
Dr. M. Vazan and Colonel Leo Orlov meet with General Skoplin, and explain that thanks to the computers that Skoplin provided, they have developed Dehominant-B, a much more powerful version of its predecessor. Skoplin is satisfied with the results and is confident that Vazan won’t disappoint him. They begin production, activating the super-computer, and Vazan assures the general that the process is running smoothly.
Willy carries the limping Barney toward the exit and tells the security guard that Barney sprained his ankle. As they present their papers, a doctor comes by and notices the symptoms, and realizes that Barney has been exposed. The security guard sounds the alarm before Willy can knock him and the doctor out. In the control room, Orlov confirms that there’s been a security breech. Meanwhile, Barney tells Willy to get out and warn the others, and his teammate has no choice but to abandon him. Willy slips by the guards and makes his escape.
Orlov confronts Barney and demands to know if he was after the computer. When Barney refuses to speak, Orlov warns him that he will either confess or suffer an unpleasant death.
In the nearby city, Willy goes to the team’s hotel room and meets with Jim, Dana, Paris, and Doug. Doug warns them that Barney only has three and a half hours. Jim checks with Washington and informs the others that they’re going ahead with the mission, and Barney knew the risks. They’ll get him out if they can, but the mission comes first. When Paris notes that no one else can handle the computer, Jim tells them that they’ve come up with the name of a young computer expert, Dr. Jerry Carlin, who is in the city. He’s a dropout and Jim figures that they’ll have to make sure he agrees to help them. When Paris wonders if they have the right to involve an innocent, Jim reminds his teammates that Vazan’s government plans to use the poison immediately. Since they can’t do anything the same way and they’re manufacturing Dehominant-B in three hours, Jim has come up with a brand new plan.
Jerry is at a café meeting with his girlfriend, Judy Moore, when the waiter calls her away for a phone call. Dana comes in and sits herself down, and shows him a printout on his background. Meanwhile, Jim is the one who has called Judy and tells her that there are problems with her passport.
Paris takes some covert photos of Jerry, while Jerry demands to know who Dana works for. She explains that Interoco has been taken over by the army, and they’re using the plant to create Dehominant-B. Jerry isn’t impressed, figuring that one more chemical weapon doesn’t make a difference, and Dana asks him to take Barney’s place and destroy the formula. When she offers him money, Jerry refuses and insists that he’s uninvolved. Dana gives him her card and leaves.
Dr. Vazan explains to the suffering Barney that his nervous system is deteriorating and his heart and lungs will soon follow. He offers the antidote in return for Barney’s explanation of how they got in and who he and Willy working for. When Barney says that they were working alone, Orlov doesn’t believe him.
Jim has pinpointed the autopsy room in the plant and says that they can access it through the furnace room, and it’s the best place to conduct their operation.
Orlov suggests that they use a truth drug on Barney, but Vazan assures him that the pain will prove too great and Barney will crack. Skoplin is called back to his embassy and tells Vazan that Orlov will make sure that nothing interferes with his work. Technician Tirkin informs Vazan that they are 40% into Phase 2, and Vazan receives a call. It’s Jim, claiming to be an acquaintance of Vazan who met him four years ago at Stockholm. He expresses interest in Vazan’s pesticides and says that they’re sending Dana over that afternoon to collect his notes so that they can nominate him for a peace prize. Vazan is hesitant to interrupt his work, but when Jim suggests that the scientific community suspects that Vazan is producing nerve gas, Vazan agrees to see Dana.
Paris and Doug bust into Jerry’s hotel room, claim to be narcotic officers, and find some (planted) drugs in Judy’s purse. They arrest Judy and Paris draws a gun on Jerry when he puts up a struggle. Once Doug leaves with Judy, Paris puts the gun away and warns Jerry that Judy could be sentenced to ten years of hard labor. When Jerry threatens to go to the consulate, Paris warns him that it won’t do any good and Jerry realizes that they set Judy up. He produces a photo of Dana with Jerry from earlier and demands more information about Dana’s plan. Jerry insists that he’s uninvolved and Paris, posing as an intelligence officer, tells Jerry to penetrate Dana’s group and tell him what he learns. The dropout reluctantly agrees and Paris tells him that they’ll contact him when they need to.
Jerry sets up a meeting with Dana, claiming that he needs the money. She starts by trimming his beard and hair. Then she takes him out into the desert where the rest of the team is opening an access hatch. Paris and Doug don gas masks so that Jerry won’t recognize and then go into the tunnels. When a cleaned up Jerry gets out of the jeep, Jim has him put on the same protective gear that they’re wearing. They go into the tunnels while Dana seals the hatch behind them. However, the tanks at the plant start overheating and Vazan orders Tirkin to feed seawater through the tunnels to cool the tanks down. In the tunnels, Jerry and the IMF are forced to run. Once the tanks are sufficiently cooled, Vazan has the conduit closed and the team manages to get through the hatch just in time.
Vazan warns Barney that if he waits much longer, the antidote won’t work. Barney refuses to incriminate the team and Orlov tells Vazan to let him die.
Willy dresses as a soldier while Jerry and Jim pose as workers. Meanwhile, Doug dresses as a soldier and escorts Paris in, who is posing as a worker. While Willy requisitions a light van, Paris break into a service closet while Doug stands guard outside. Paris goes to some pneumatic messenger pipes and attaches some thermite tape, and then burns through one pipe.
Jim takes Jerry to the autopsy room. Upon seeing the bodies of dead monkey subjected to Dehominant-A, Jerry realizes that it’s all real. However, he quickly recovers, pointing out that there are already of deadly weapons in the world and one more won’t make a difference. Jim says that he’s just there to make more that one more doesn’t come into the world, but tells Jerry that they don’t have time to argue and gives him the schematics for the computer.
Paris removes the pipe section, puts a fake message cylinder in, and reattaches the pipe. It contains an envelope confirming that Jim and Jerry are Interoco employees. Paris then leaves with Doug.
Jim tells Jerry to destroy the dehominant before it’s produced and erase the computer formula. He knows all about Jerry’s background, but Jerry hints that he’s working for the authorities. However, Paris and Doug come in and Jerry realizes that he’s been tricked. He sets off the alarm before they can stop him and Orlov and his security guards come running. When they enter the autopsy room, they find a monkey that has apparently set off the alarm. Orlov tells his men to secure the monkey, unaware that Jim and the others are hiding in the adjoining furnace.
Dana arrives at the plant and Vazan okays her entrance. Orlov reluctantly agrees and has her escorted to Vazan’s office. As she pulls up, Dana signals Jim. They’ve tied up Jerry, but Jim tells him that they need his help as much as he needs theirs. He points out that Jerry was willing to let them get shot, but Jerry insists he was only trying to help Judy.
After requisitioning the van, Willy pulls up in front of the main building where Dana has parked and fakes a flat. Using the van as cover, he removes a collapsible filing cabinet from beneath Dana’s car and puts it in the van, and then drives off.
Dana starts to interview Vazan as Orlov comes in and introduces himself. He sits down to observe the proceedings and Dana starts to review Orlov’s work on pesticides.
Paris creates a mask of Vazan and Willy brings in the collapsible filing cabinet, as Jerry observes the proceedings in amazement. When he wonders why they’re doing it, Paris tells him that if nothing else, they have a friend nearby who will die in 20 minutes if they don’t rescue him.
Dana keeps the interview going until Orlov objects. She suggests that he leave them alone and Vazan agrees. Once the colonel leaves, Dana shows him a formula and gets close enough to hit him with a drugged needle-ring. She then signals Jim, while Paris finishes his disguise as Vazan and Willy and Doug assemble the filing cabinet. Paris gets into the filing cabinet and Willy takes him out. Jerry points out that Paris won’t fool anyone and reminds them that they won’t get anywhere without him, and Jim says that they’re going to try.
Willy delivers Paris to Vazan’s office and removes Vazan in the same filing cabinet. As Paris orders the security guard to let Willy into the autopsy room, Orlov comes back and Dana assures him that she has everything she needs. When Jim and Doug unload Vazan, Jerry assumes that Paris has failed until Doug explains that it’s the real Vazan.
Paris and Orlov go to see Barney, who is going fast. As Paris leans over Barney and offers to save him, he slips a transmitter into Barney’s ear. Paris then use a pocket penlight to examine Barney’s eyes and signals Jim with a hidden transmitter. Jim tells Barney that Paris is Vazan and has him blink twice to signal that he can still hear. Paris gets the signal and uses the penlight to signal Jim back, and Jim tells Barney to confess that two technicians helped him, including Tirkin. He does so, saying that the technicians found a way to get around the progress indicator, and then collapses. Paris confirms that he’s dead and has a guard take him to the autopsy room.
As Orlov interrogates the technicians, the guard drops Barney off. Doug examines him and warns Jim that their teammate isn’t going to make it. As Jerry looks on, Doug administers to Barney, who finally revives. He’s too weak to move and Jim assures him that he’ll take care of the computer.
As Orlov interrogates Tirkin, Paris interrupts and asks for the current programming check. The colonel has the technicians locked up and orders Paris to replace them. He calls Jim, who asks Jerry again if he will help them. Jerry still refuses and Jim has Barney run down the steps, but Barney warns that he can’t handle it. Impressed against his will, Jerry agrees to help the team with the computer. Jim has no choice but to accept his offer, and Jerry gets the necessary information from Barney. Jim then takes Jerry to the control room and introduces themselves as the two new technicians. Orlov checks them briefly and says that he doesn’t recognize them, and Paris explains that they were processed before he arrived. The colonel calls for their dossiers and the man in the file room checks the faked Ids that Paris sent through earlier.
Willy takes Vazan out to the van and drives away with Barney and Doug. Meanwhile, Paris goes over the programming check and tells Orlov that there has been some subtle sabotage. He assures Orlov that it can easily be repaired and puts Jerry to work. Jerry starts the false programming, When one of the workers notices something is amiss, he calls the control room. Paris takes the call, claims he’ll try to fix it, hangs up, and tells Orlov that it’s going well. However, another technician calls to report the same problem. Orlov takes the call and realizes that something is wrong. Paris leads him away and offers to explain, while Jerry erases the formula. Jim writes out a message to Paris telling him to split and then knocks out Orlov. They walk casually out of the computer room and Willy escorts them past the security guard who he had knocked out earlier. When the guard spots him, Willy knocks him out again while Jim disposes of the other guard.
Doug drives the van out of the complex just ahead of the security teams, while Jerry wonders what they’re going to do with Vazan. Jim assures him that they’ll put him somewhere so he can’t develop Dehominant-C and Jerry admits that he believes them... now. They rendezvous with Dana, who is waiting with Judy. They all get into a school bus and make their escape.