The Department of the Interior is working with the Phoenix Foundation on a "Save the Wilderness" program to map out territory to set aside as a national preserve. The Department representative Joanna flies MacGyver out into the wilderness and drops him off to place five stationary radio markers. Joanna and Pete Thornton then fly back to the Foundation's lake station to coordinate efforts. Pete assures Joanna that MacGyver is a wilderness expert and that he'll soon be ahead of schedule.
As he starts off, MacGyver finds an Indian totem pole and a nearby skeleton, and concludes it's there as a warning. He hears a strange animal roar in the distance, and continues on his assignment. He places the first radio marker, which shows up on the station map. While traveling through the wilderness, MacGyver spots a seemingly abandoned freighter on a lake and fixes a nearby rowboat to go out and investigate. On board, MacGyver confirms the ship is abandoned and the crew seemingly disappeared in the middle of a meal. He also finds an enormous handprint on a table. He goes to the bridge but a large humanoid creature covered in fur smashes through the window. MacGyver ducks beneath a table as the creature smashes into the bridge. Once it starts smashing the equipment, MacGyver slips through a door and jams it behind him.
MacGyver moves through the ship and spots someone running away. He manages to corner the person, only to discover that it's a young girl. She tries to run away and he grabs her, but she doesn't seem to speak English. The creature smashes through the jammed door and comes after them. MacGyver seals a bulkhead door and gets up onto the deck with the girl. The creature cuts off their escape and they're forced to jump overboard and swim to shore. On shore, MacGyver still is unable to get the girl to respond. He has no choice but to start hiking back to civilization and invites the girl along. She follows him into the woods.
Pete starts to worry when MacGyver doesn't plant the second marker. Meanwhile, MacGyver tries to befriend the girl by offering her water but she still doesn't trust him or respond in English. As they continue, they're unaware that the creature has come ashore behind them.
MacGyver makes camp for the night and continues talking to her in various languages. She reacts when he speaks Russian, and then finally admits she speaks English. She introduces herself as Karin Graff, and explains that her father took work in Juneau, Alaska. Her cousin Alexander agreed to help her stow away on the freighter, which was traveling from Russia to Juneau. However, when the ship stopped in the lake the creature somehow got onboard, killer her cousin, and frightened away the rest of the crew. MacGyver promises to get her to safety. However, they're interrupted when three figures emerge from the woods: local Native American trappers Joe and Dave Whales, and their uncle Len. They ask to warm up by the campfire and MacGyver agrees. While they rest, Karin realizes that they know about the creature. Dave and Joe are skeptical there's a strange creature at large, but their Uncle Len claims that it's Sasquatch, the same creature he saw as a child. As they prepare to bed down for the night, they hear more animal roars and see strange lights in the distance. The next morning, the Whales slip away before Karin and MacGyver wake up.
At the station, Joanna suspects that MacGyver has decided to just kick back and go fishing, but Pete doesn't believe it.
As they go through the woods, MacGyver and Karin hear an electrical sparking noise. They go to investigate and find men welding at a nearby pipeline. Karin starts to approach them but MacGyver realizes that they're the pirates tapping into the oil line. The men are the crew from the freighter, and the electric arc lights caused the display the previous night.
MacGyver has Karin hide while he gets to high ground to signal for help. However, one of the pirates finds her and takes her to the others. Their leader, Bench, wants to know who else accompanied her. She claims she's alone but Bench isn't convinced. He has his man Tenon take her to the ship for safekeeping. MacGyver, having heard her scream, doubles back and using his fishing line and pole to blind Tenon and stun him long enough to knock him out. He runs into the woods with Karin while Bench and the others discover that Tenon is unconscious.
MacGyver doubles back to the oil pipe, activates all four markers, and puts three of them in the pipe. At the Phoenix station, Joanna and Pete note that the three markers are moving fast and figures it's a signal. Pete takes a helicopter out to the stationary fourth marker's location.
MacGyver gets Karin to high ground so Pete can see them when he arrives. However, the creature arrives and attacks MacGyver. It knocks him down and goes for Karin, and he leaps on its back. It throws him off, but MacGyver pulls the creature's head with him: it's a man in a costume, using a voice distorter. He charges as MacGyver, who sends him flying by using a fallen tree. Bench arrives and prepares to shoot MacGyver but Pete arrives in the helicopter and has the pilot knock the pirate leader down a hill with the landing skid.
Later at the station, MacGyver wishes Karin well as she heads to Juneau to be with her father. He promises to see her once he's finished planting the radio markers. Joanna gives him a new set of markers and wonders if MacGyver really was fooled by a man in a costume. MacGyver admits that he was beginning to wonder how real the legend of Sasquatch was. They hear Sasquatch's nearby: it's Pete, playing a tape recording the pirates made and played over loudspeakers on the freighter. They figure that Sasquatch is just a legend… until they hear a strange animal roar in the distance.