MacGyver is climbing the rock face of a high peak, the Widowmaker, with his friend Mike Forester. Mike gives him expert advice as he slips and hangs from his cable, and with her help MacGyver manages to pull himself up. They pause for lunch and Mike makes a mildly suggestive comment, then apologizes. She insists she wants more from him then just friendship but MacGyver insists that it’s their friendship that matters. Blinking back tears, Mike insists on pressing ahead and they ascend, Mike in the lead. As she anchors her line, she slips and loses her grip, falling before her safety line stops her. She hits her head on a rock edge and is knocked unconscious as her strap starts to part. MacGyver can only look on as the harness breaks and she falls to her death.
Over a week later, Pete and Nikki are at the Phoenix Foundation and wondering why MacGyver isn't returning their calls after the copter team rescued him. He's been staying at Pete's cabin since and Pete figures that MacGyver is blaming himself. Pete doesn't understand how Mike could have slipped, and explains to Nikki that MacGyver and Mike went way back.
Peter goes to the cabin and tells him that everyone at the funeral understood why he wasn't there. MacGyver wonders what there is for him to return to and refuses to take Pete's advice to take on assignments. He snaps at his friend and then apologizes, explaining it was his fault. Pete doesn't buy that and insists there was nothing MacGyver could do about it. MacGyver tells him that he wants to be left alone and Pete reluctantly leaves.
At MacGyver's houseboat, a shadowy figure breaks in and draws a knife. He checks MacGyver's answering machine and hears a call from Nikki saying he's been gone for two weeks and they’ve left messages for him at Ellards' General Store. The figure sees a flier for the Widowmaker with an Ellards' label on it. The figure hears another message from Pete and smashes a photo of MacGyver and Pete together, then takes out a blow torch and burns a message into the wall: "R.I.P. MacGyver." He then takes photos of the wall and leaves one on the floor.
The next day, Nikki asks about Pete, who admits that MacGyver seems to have lost any spark of life. She suggests MacGyver needs someone who isn't so close that he can open up to. Pete reluctantly agrees with her and gives Nikki directions. She stops at Ellards' General Store and buys groceries, and the owner admits MacGyver hasn't visited. As she tries to start her car, Nikki discovers it doesn't work. A farmer offers to help and checks the engine, getting it to start. He warns the spark plugs are worn and suggests she have her friend check it when she gets there. Nikki drives on to Pete's cabin and discovers the kitchen is a mess. She finds him lying out by the lake and he insists he doesn't want her help. She tries to goad him into getting his act together and MacGyver tells her to leave and starts to storm off.
MacGyver finally explains that he pushed Mike away emotionally and she fell. As they go inside and he tries to explain, MacGyver notices photos hanging from the ceiling of the cabin. The photos are from Murdoc's last attempt to assassinate MacGyver and Pete. A burn-scarred Murdoc opens fire with a flame-thrower, and Nikki recognizes him as the farmer from the general store. When Murdoc kicks in the door, MacGyver uses a mattress to shield themselves long enough to get out the rear entrance. They get to their cars and discover the tires on MacGyver's jeep have been slashed. They get into Nikki's truck, unaware that Murdoc has rigged it to explode in 60 seconds. The doors lock automatically and the wipers come up with a goodbye message on a piece of cloth. MacGyver hears the timing device and kicks out a rear window. They get out seconds ahead of the bomb going off.
Nikki starts to walk down the road but MacGyver stops her when he notices that Murdoc has mined the road. MacGyver takes the battery out of his jeep, attaches it to a radio antenna with jumper cables, and waits for Murdoc to investigate the explosion. When Murdoc arrives, MacGyver uses the antenna to set the flame-thrower tank on fire. Nikki and MacGyver run for the mountain while Murdoc abandons the flame-thrower just before it explodes. Murdoc goes up the road, avoiding his mines, to get climbing rope and a rifle. MacGyver uses a rope and pulley to climb up a telephone pole, tap into the line using a bracelet and his Swiss Army knife, and send a Morse Code message to Ellard to call for help. Ellard, an old Navy signalman, is on the phone and understands the code. Murdoc arrives and fires off a shot, but MacGyver slips and the first bullet misses. He climbs down and they go the only direction they can: up.
Pete arrives at MacGyver's houseboat and sees Murdoc's R.I.P. message on the wall. Realizing who is responsible, Pete calls his secretary who informs him that Ellard has called with MacGyver's message, then arranges a helicopter to take him to the Widowmaker.
MacGyver and Nikki get to the cliff edge and MacGyver temporarily freezes up. He says they can free-climb to a ledge and find cover. As Murdoc closes in, they climb down the rock face and MacGyver finds Mike's anchor line. He tells Nikki to wait and descends to where Mike's rope is anchored. He uses it to climb down and the line up to Nikki and she lowers herself down while he anchors the line. They pause to take a break and Nikki finds Mike's chalk bag. She also sees the frayed harness and MacGyver has to accept that it wasn't his fault and there was nothing he could have done.
MacGyver uses the rope to descend to the ledge below and cover, while Murdoc arrives above. As Nikki comes down next, MacGyver makes climbing harnesses out of the rope for when they need to climb up after Murdoc is captured. Murdoc swings down on his own rope and slashes at them, cutting MacGyver's arm and knocking Nikki over the ledge. As she hangs on, Murdoc moves in for the kill. MacGyver throws the chalk from Mike's bag into the assassin's eyes, buying himself a few seconds. Murdoc swings back and MacGyver grabs his support rope and holds it up. Murdoc cuts it with his own knife and falls over the side, screaming on the way down. The killer plummets to his seeming death and MacGyver pulls Nikki to safety. He admits that he's doing better.
MacGyver prepares to climb back up and Nikki refuses to move. He offers to secure her in case she dozes off overnight and Nikki has no choice but to go up with him. She complains about his extreme changes in attitude and they make the ascent.