Nuclear physicist Joseph Collins arrives at an abandoned building and picks up a briefcase filled with money. He gets a call informing him the rest is in a Swiss Bank account and he tells the buyer, Haig, that the material is in the same place as the previous year. Collins is unaware that federal agents are listening in.
Jim picks up his briefing from a photographer and is informed that Collins has stolen 50 kilograms of plutonium and is selling it to an unidentified foreign interest. Their representative, Haig, is to take delivery on noon in two days. The IMF must recover the plutonium.
Jim assembles the usual team and they make sure Collins hasn't made any long-distance travel in the last few weeks. They’re going to be using an area of the city flattened by an earthquake and cleared for repairs, and they will be working at a local police station that Collins is familiar with. They have a phony tape recorder with a pre-recorded broadcast ready and planted at Collins’ apartment, and Casey has several drugs that will lower Collins’ body temperature and weaken him. Casey warns that the spirit gum won’t last more than 12 hours.
At his apartment, Collins is listening to the radio and hears a broadcast about the unstable Middle East situation. Max Bander, an attorney, calls Collins to inform him that his apartment is being watched by Jim and Willy. Bander is operating on behalf of an American interest and offers him double what he’s receiving in return for the plutonium. He asks for an hour to think about it then prepares to leave but Willy arrests him on a murder charge, for someone Collins has never heard of. Willy leaves with Collins and Bander gets his license plate number. Bander calls a private eye he has on retainer, Sager, to check out the situation
Collins calls his lawyer, and Casey tells him the man isn’t available and they’ll leave a message. Willy takes Collins to a wing under construction and put him in an interrogation room where the radio is broadcasting more fake Middle Eastern news and one of the IMF agents drops a newspaper with a Middle East headlines. Meanwhile, Sager tries to figure out who Willy is but no one has heard of him. Sager tries to get into the renovated wing but is turned away, so goes to the floor above and lowers a microphone down the ventilation shaft. He listens in as the radio broadcasts a growing state of war. A missile strike is launched and Willy races to the window where the IMF is playing a fake projection. A fake nuclear bomb burst goes off and Willy uses a needle to knock out Collins. Casey starts putting makeup on him and Jim calls their operation base in the suburb of Bridgeton to tell them they’re on-schedule, as Sager listens in.
While workers plant explosives charges in the flattened buildings near Bridgeton, the team arrives with the unconscious Collins and moves him into position. Sager sells the tape to Max and leaves, and Bander’s employer Smith tells him to go to Bridgeton to investigate.
Collins wakes up to find himself working on an assembly line where old men are putting food into cans, while armed men watch them. He finds a mirror and discovers that he has aged twenty-eight years. Jim comes in as a military officer and demands to know what’s going on. It turns out Collins is a “Class 9” and has two days left. Jim orders him confined and Collins is put in a cell with Barney, a Caribbean student and prisoner of war. Collins looks on as old male prisoners are put in a room across the hallway, then gassed to death. Looking at the dates inscribed on the walls, Collins believes that it’s the year 2000 and he’s 28 years in his future. Barney explains that as a Class 9, he was near ground zero and went into shock like others.
The IMF stages a phony air raid and set off the explosives charges. Max and his henchmen, watching from a distance and using a parabolic microphone, are left to wonder what’s going on. The explosions knock the cell open and Barney and Collins slips out. Collins takes a gun from a guard and they’re forced to hide when Jim arrives. Collins forces Barney to take him out but Barney just laughs and says that all prisoners are executed when they reach age 65, and Collins is just two days shy of his 65th birthday. Barney agrees to lead him out but guards shot them and after Collins shoots at them briefly, they take refuge in a building. Bander calls his superiors and tells them that they’ll continue to watch Collins until they find out where he hid the plutonium.
Barney and Collins come to a sealed door and Barney sends a signal. Collins overhears Jim talking to other men and looks in to find a military command center. They discuss how they’ve depleted their nuclear weaponry. The guards capture Collins and Barney but Collins demand to be heard. Jim notices that Collins’ aging makeup is starting to melt. Collins offers them 50 kilos of refined plutonium and offers to give them its location, and Jim demands he pinpoint it with no guarantees. Collins finally shows them the canyon where it’s located and Bander gets the information as well from the parabolic mike.
Collins is taken back to his cell while Haig and his men are already digging up the plutonium. Bander shows up and a gunfight starts. The IMF arrives as Haig’s side emerges triumphant and starts to take the plutonium.
In his cell, Collins discovers that his cell door is unlocked. He goes outside only to find that everyone has vanished. He realizes his makeup is melting off and hears the police sirens approaching. Realizing he’s been tricked, he bursts into hysterical laughter.