MacGyver is traveling out to the wilderness to take four Phoenix Foundation employees on a stress-relaxation overland hike. Meanwhile, one of the four men pulls over at a rest stop. As he goes in, the radio broadcaster comes on the air saying that a prison bus has overturned and 12 prisoners have escaped. One of the prisoners slips into the rest stop, kills the Foundation employee, and hears the radio mentions roadblocks. The prisoner sees the brochure on the stress relief program, steals the dead manâ€™s wallet, and drives to the Foundation base camp.
At the base camp, the three employees and the prisoner meet with MacGyver. None of the men have met each other before. The four men, Henry Colter, Tony Parisio, Dr. Fred Beam, and Chuck Laraby, introduce themselves. MacGyver talks about the dangers of stress—the â€œinvisible killerâ€—and they start their hike. As they proceed to Cascade River on the first leg of their trip, MacGyver leaves the map behind, insisting he knows the route, but Parisio insists on taking it just in case.
At the rest stop, two boys find the dead body in the woods.
As the men proceed through the forest, Dr. Beam has trouble with his pack. MacGyver adjusts it and notes itâ€™s set for someone much smaller than Beam, and the doctor claims his son used it last. Laraby complains about his shoes not fitting, causing blisters. Colter picks some berries and pockets them.
The police find the dead Phoenix employee and call Pete in. He meets with Sheriff Maxwell, who is heading up the search.
When Laraby starts to tire, MacGyver calls a break. Parisio tries to tune in a ball game on his radio. When a newscast about the prison bus comes on, Beam angrily tells him to turn off the radio. They struggle and Beam knocks it to the ground, breaking it. The doctor apologizes, admitting he has a lot on his mind. As they go, Parisio nervously scans the landscape with binoculars. When MacGyver asks why, Parisio claims heâ€™s worried about bears.
The five men arrive at the suspension bridge across the Cascade River. Laraby admits that he has acrophobia and on his way across, freezes halfway. MacGyver comes up behind him and tries to get him to safety, but Laraby panics and knocks him over the side. MacGyver hangs on while Colter comes out, gets past Laraby, and pulls MacGyver to safety. Colter then knocks Laraby unconscious and hauls him off the bridge to the other side. Laraby recovers and apologizes. When MacGyver points out that he didnâ€™t have acrophobia listed on his application, Laraby claims that heâ€™s just hiding it out of pride.
Despite Peteâ€™s insistence, Sheriff Hubbard refuses to send men out to check on MacGyver and the others. Pete refuses to wait and insists on going to the base camp and Hubbard sends Officer Walker with him.
The men stop near a lookout tower, and the park ranger, Liz, comes out with a gun. She demands ID and informs them about the escaped prisoners. Once she checks their ID, Liz invites them in for coffee.
Pete and Walker arrive at the base camp and the officer finds a hank of fair. She figures that the prisoner cut his hair for disguise and then took the place of the man he killed.
As MacGyver and Liz take a stroll, they discuss the escape. Liz notes that the radio broadcast didnâ€™t give descriptions of the escaped prisoners. She talks of how she took on the job ranger to help get over her divorce and gives MacGyver a hand-carved birdcaller so he can have company when he wants. Meanwhile, the men start growing suspicious of each other and Parisio taunts Laraby.
Pete and Walker go to the Cascade River suspension bridge and discover that someone cut the cables loose after crossing over it. They realize the lookout tower is the next stop on the trail after the bridge and go back to contact Liz by radio.
As they continue, Laraby claims that he recognizes Colter as a man heâ€™s been faxing back and forth with at the Foundation. They make camp for the night and MacGyver notices that Beam fieldstrips his cigarettes. Beam angrily says that he picked up the habit in the Marines. The men discuss which of them could be a prisoner and suspicions continue to mount.
The next morning, MacGyver, Parisio, and Laraby discover Beam dead in his tent, strangled. MacGyver notices some holly berries lying on Beamâ€™s sleeping bag and checks the coffee. The coffeepot is filled with holly berries, enough to have killed them when they drank it. They figure Colter killed Beam and poisoned the coffee to eliminate the rest of them once he left. Parisio wonders why Colter would kill MacGyver, who is the only one who knows how to get back to civilization, but MacGyver realizes that Colter can force Liz to help him.
Back at the sheriffâ€™s station, Liz finally makes contact with them. Someone took the fuse out of her radio. However, as Hubbard starts to warn her, Colter arrives at the tower, takes her rifle, and smashes the radio.
A little later, MacGyver, Parisio, and Laraby arrive at the tower. Colter has taken Liz and left the radio. MacGyver asks Parisio and Laraby to fix the radio while he goes after the prisoner. He catches up to him and uses the birdcaller to warn Liz heâ€™s nearby. He then gets ahead of them and rigs a small hutch of branches planted in the ground and bent over. MacGyver starts a fire underneath them, ties fishing line to the branches, and hides in a nearby tree. When Colter comes up, he spots the fire and investigates. MacGyver pulls the fishing line, causing the branches to spring open and spray ash in Colterâ€™s face. MacGyver quickly knocks the prisoner out.
The police find a second corpse and call Pete and MacGyver to the scene. They realize that itâ€™s a second Phoenix employee.
MacGyver and Liz take back the rifle and escort him to the tower. Laraby tells them that Parisio managed to fix the radio but then took off into the woods. They give him the gun and tell him to watch Colter and then go up into the tower. They discover the radio is working but the microphone is missing. Below, Laraby considers Colter suspiciouslyâ€¦ and then asks why he poisoned the coffee. Laraby admits he killed Parisio, and Colter convinces him that their best chance of escaping is to work together.
MacGyver and Liz spot Laraby and Colter talking together and lock the door. Laraby orders them to come down and fires a warning shot. MacGyver quickly takes a telescope, coats the tube with grease, and soaks a wad of cotton in vinegar and red pepper. When Laraby comes up, MacGyver uses a bullhorn to propel the cotton through the telescope, hitting Laraby in the face and causing him to stumble back over the railing. He breaks his leg in the fall and Colter takes the rifle.
Ignoring his fellow prisoner, Colter takes the rifle and goes up to the tower. Liz shows MacGyver a hatch in the floor used to haul up supplies. When Colter enters the tower a minute later, he doesnâ€™t see MacGyver and Liz. He steps into the middle of the room and MacGyver calls out from where heâ€™s hiding in the rafters with Liz. Colter steps backâ€¦ on to a rug covering the open hatch. He falls into the rope snare that MacGyver set and ends up dangling halfway to the ground.
Later, Hubbard takes the prisoners back into custody and Pete insists theyâ€™ll continue the project, and name it in honor of the two dead employees. When Hubbard gets a call from his wife that his kids have the measles, he volunteers to be the first one to sign up for the anti-stress program.