DXS agent Pete Thornton arrives on the docks to meet MacGyver as he returns by ship after escaping through the Iron Curtain with a list of terrorists. He's unaware that an East German agent, Curt Neilson, is watching him. As MacGyver gets off the ship, he notices a girl, Lisa Allen, having trouble fishing. She admits she doesn't have a lure so MacGyver makes one for her. She thanks him and he goes on his way as she promptly catches a fish. Pete meets with MacGyver and Curt's hired local thug Barrett goes to get his accomplice, Crisp. Pete and MacGyver spot the enemy closing in and Pete draws their fire so MacGyver can escape with the list. Barrett shoots Pete and MacGyver knocks down Crisp. With the East Germans closing in, MacGyver unfastens the base of a lamppost and hides the list inside. He then spots a policeman writing a ticket and goes to him for help. However, the policeman is Polk, one of Neilson's men in disguise, and knocks him out.
At DXS headquarters, Pete confirms that Neilson is responsible and orders his men to find the East German.
Neilson takes MacGyver to a warehouse and has him searched, but they don't find the list. When MacGyver refuses to tell him what he wants, Neilson injects him with a poison and explains that he will first suffer from dizziness and hallucinations for three hours. After that, the pain will be excruciating and ultimately kill him. Neilson offers him the antidote if MacGyver gives up the list. He then has Barrett attach a wristwatch set to six hours to remind MacGyver how long he has to live.
Crisp and Polk lock MacGyver up. Meanwhile, Neilson calls his superiors and assures them he'll have the list shortly. MacGyver rigs the bed as a crude slingshot by fastening its springs to the door. However, he starts to feel dizzy. Recovering for the moment, MacGyver uses his belt as a crude hose to run water from the sink to a nearby electrical outlet and into the switchbox below. Crisp and Polk go to investigate just as the box shorts out. When they come to the door, MacGyver releases the bedframe and it slams into the two men and knocks them against the opposite wall. MacGyver runs outside but collapses from the effects of the poison. He manages to get away but is almost hit by a truck. Meanwhile, Neilson figures that MacGyver will be too confused to call for help and they have three hours to find him.
A confused MacGyver staggers down the street. Lisa and her two friends are walking by when she notices MacGyver. Her friends figures MacGyver's drunk or on drugs and warn Lisa that she's a runaway and can't get involved. She insists on helping MacGyver and her friends leave. Lisa sees a policeman and starts to get him, but MacGyver remembers Polk ambushing him and tells Lisa not to involve the police. She takes him to an abandoned building that she has set up as her home, having hooked up the lights to an old car battery. MacGyver doesn't remember her and she offers him some food. He gets her to tell about how she left home to avoid a physically abusive father after the authorities failed to do anything. Now Lisa has schoolbooks and plans to get a diploma. They're interrupted when MacGyver starts to feel more pain.
Barrett and the others talk to Lisa's friends, who tell them about MacGyver. Meanwhile, MacGyver hallucinates Neilson coming in and trying to kill him while he sleeps. Once he wakes up, he begins to remember what happened and that the fact there's an hour and thirty minutes on his watch is significant. MacGyver then remembers who he is and that he stashed the list. Lisa comes in to tell him that three guys are snooping around outside. Neilson's men set off Lisa's crude burglar alarm as they come in. MacGyver rigs a TV tube to the car battery so it explodes when the door is opened, then uses a transistor radio to draw their attention. Crisp opens the door and the explosion goes off, drawing the others. MacGyver and Lisa head upward and MacGyver tosses a fire hose out the window to climb down. Barrett and the others arrive and figure MacGyver has escaped. Once they're gone, MacGyver and Lisa emerge from hiding and leave.
Back on the streets, MacGyver tells Lisa where the list is and to call Pete while he goes to the warehouse. He explains that he's with the government and the list is important, and Lisa agrees to help. Once she's gone, MacGyver goes to the warehouse, sneaks by Crisp, then lets the air out of the tires of a nearby car. When he comes to investigate, MacGyver slams the car door in his face. MacGyver then goes inside and finds Neilson's office. With only twenty-two minutes left, MacGyver starts to put together a plan. He rigs several water bottles up in the rafters by a rope, then places a large piece of plywood. He then ties the rope around a smoke alarm and sets it on fire. When the smoke alarm goes off, Barrett and Polk go to investigate. MacGyver offers to surrender, then release the rope that he's holding in place with his foot. When he stands up, the water bottles drop and roll off the ramp, hit some barrels, and knock the bad guys down.
As Lisa arrives after calling Pete, MacGyver spots Neilson and goes after him. The weakened MacGyver goes down and Neilson throws the antidote down a sewer grate. MacGyver knocks him out. He then grabs a nearby metal rod and starts hitting it on a fire hydrant. As he works, MacGyver explains that the impact causes temporary atomic alignment, causing a magnetic field. He then extends the rod through the sewer grate and manages to grab the metal container holding the antidote. With just two minutes remaining, MacGyver recovers the antidote and takes it.
Later, MacGyver recovers the list from the lamppost and shows it to Lisa. He tells her that as a reward he's arranged for Pete to get her a government scholarship.