MacGyver and his long-time friend Mike Forester are rock-face climbing the Widowmaker, a huge mountain. She guides MacGyver through the procedure and helps him out when he slips. They stop for lunch but when Mike flirts with him, MacGyver gets uncomfortable and she stops. She wishes they could be more than friends but MacGyver admits he doesn't feel that way and he values her friendship. Mike starts climbing ahead and anchors her line. However, she slips and falls, hitting her head on the rock wall. She dangles unconscious by her safety line, but MacGyver can only look on in horror as the harness break and she falls to her death.
A week later, Pete and Nikki are trying to get through to MacGyver, who is staying at Pete's cabin. Pete wonders how Mike could have slipped and notes that Mike and MacGyver go way back. He goes out to the cabin and finds his friend sitting outside. When Pete says there are assignments waiting, MacGyver says that he isn't interested and then explains that it was his fault that Mike slipped. When Pete tries to assure him it wasn't his fault, MacGyver angrily tells him to leave.
A shadowy figure breaks into MacGyver's houseboat. He checks the answering machine and finds that Nikki has left a message asking why he hasn't been returning her calls. She mentions the local grocery store and the intruder finds a flier for the Widowmaker with the store name on it. He smashes a photo of MacGyver and Pete and then uses a blowtorch to write the words "R.I.P. MacGyver" on the wall. Finally, the intruder takes photos of the message and leaves one on the floor.
Nikki checks in with Pete, who is worried that his friend has lost any interest in life. She figures that MacGyver needs someone who will be tough with him and can get him to open up. When Peter reluctantly agrees, Nikki drives to the cabin. She stops at the general store first to buy some supplies. When she tries to start her car, it doesn't work. A local wearing a billed cap over his face offers to check it and gets it working for her. She mentions that her friend is good with machines and the local suggests she have him check the engine when she gets there.
Nikki arrives at the cabin and finds MacGyver out by the lake. He tells her to leave despite her efforts to prod him into doing something, and starts back to the cabin. When Nikki demands an explanation, MacGyver says that he rejected Mike, and she was so distracted she fell. However, as they enter the cabin they find photos dangling from the ceiling. All of them are pictures of the time when Pete and MacGyver were the targets of a photo-taking assassin: Murdoc. A badly scarred Murdoc shoots a flame-thrower at the cabin. Nikki recognizes him as the local from the general store. MacGyver uses a mattress as a shield to block the flames long enough for them to escape. They discover Murdoc has slashed the tires on MacGyver's jeep. They go to Nikki's car and try to drive away, but the doors lock and the engine won't turn over. The windshield wiper comes up with a message from Murdoc: a goodbye message. Realizing there's a bomb in the car, MacGyver kicks out the rear window and they escape just in time.
Nikki starts to head down the road but MacGyver spots tripwires and stops her just in time. Murdoc has mined the road, and now he's coming to investigate the explosion. MacGyver quickly rigs his jeep battery, jumper cables, and a radio aerial into a makeshift electrical prod. When Murdoc arrives, MacGyver sets off the flame-thrower's fuel tanks and they run the only way left: up the mountain. Murdoc gets it rid the flame-thrower then makes his way through the mines and gets a rifle and rope.
In the woods, MacGyver uses a rope and pulley to make linesman climbing gear and goes up a pole. He taps into the line to send a Morse code message to Ellard, the grocery store owner. Ellard, a retired Navy signalman, understands the message and calls Pete. MacGyver slips, narrowly avoiding Murdoc's first shot. They descend and proceed up the mountain.
Pete goes to the houseboat and upon seeing the message, realizes who is responsible. He calls to arrange a helicopter transfer to the mountain.
MacGyver and Nikki get to the top of the mountain and have no choice but to climb down until they can find cover. MacGyver goes down first and find's Mike's anchor line. He uses it to lower Nikki down and as they pause, they find Mike's chalk bag. Nikki sees the frayed harness on the end of the line and points out that Mike died because of an accident, not because of anything MacGyver did.
MacGyver descends to the next ledge and brings Nikki down, and they take refuge beneath an overhang. However, Murdoc swings down and cuts at them with his knife. He knocks Nikki over the ledge and slashes MacGyver's arm. While Nikki hangs on to the ledge, MacGyver manages to blind him temporarily with Mike's climbing chalk. When MacGyver swings back, MacGyver unfastens the rope from his climbing harness and then holds up the rope so Murdoc cuts his own line. He falls backward, seemingly to his death, and MacGyver pulls Nikki to safety.
As MacGyver prepares to climb, Nikki refuses to move. He jokingly offers to tie in her place so she won't roll over the ledge when she dozes off. Nikki gives in, complaining about how she can't keep up with his changes in attitude.