MacGyver convinces his high school friend, rock star Roxy Yates, to do an anti-drug rock video as part of the Phoenix Foundationâ€™s â€œdonâ€™t do drugsâ€ program. The video is shooting in Chicago, and Pete and MacGyver go the studio to watch the filming. The director, Eve, is unhappy with Roxyâ€™s performance and claims that sheâ€™s lost something. Pete objects, but Eve warns him that if he wants a decent video, he needs to get a different performer.
MacGyver goes to Roxyâ€™s trailer to talk. Meanwhile, Roxy is meeting with her manager, Frank Rogan. She accuses him of stealing her profits and insists she has the evidence to prove it. Rogan insists that his operation is legitimate and that she isnâ€™t the performer she once was. He gets angry and starts to threaten Roxy as MacGyver arrives. The manager leaves and MacGyver discusses their time together in high school. He asks how Roxyâ€™s twin sister Carla is doing and Roxy insists that Carla is fine. They go back to Roxyâ€™s penthouse apartment and take the express elevator. Halfway up it stops and MacGyver climbs up to check the cable. The mounts are loose and getting looser. He gets Roxy up to the top of the car and onto the side pipes just as the cables slip and the car plummets down the shaft. Although Roxy isnâ€™t as good a rock climber as her sister, she easily manages to make it to the top of the shaft along with MacGyver. They get the penthouse elevator door open and get inside. MacGyver wonders if Rogan was angry enough to try and kill her, but Roxy insists that the person responsible is her sister Carla.
MacGyver goes to see Carla, an artist. Sheâ€™s doing paintings of the mountains she climbed, some of them with Roxy. She admits that Roxy hasnâ€™t gone climbing with her recently. When MacGyver mentions Roxyâ€™s accusation, Carla notes that her sister has had other accident that she blamed on Carla. She explains that Roxy had a breakdown and spent a year at a psychiatric hospital, Pine Valley.
MacGyver goes back to the studio and spots Rogan leaving Roxyâ€™s trailer. As he drives away, MacGyver finds Roxy, who assures him that the evidence isnâ€™t in the trailer. Roxy then says that Carla called her and gloated about how she told MacGyver about the breakdown. The rock star insists that Carla has fixated on everyone close to her and now sheâ€™ll be coming after MacGyver. Roxy tells MacGyver not to turn against her.
Back on set, Roxy performs and even Eve is impressed with her this time. MacGyver tells Pete whatâ€™s going on and asks him to speak to the psychiatric hospital.
Later, Rogan goes to Roxyâ€™s penthouse apartment. Roxy is seemingly in the next room and invites him to have a drink. As Rogan pours himself a drink, he thanks her for agreeing to give him the papers and drop the charges against him. She calls out that the papers are on the balcony. Rogan goes out and starts reading them, and Carla comes out and shoves him over the balcony.
MacGyver and Pete arrive at the hotel where the police have already confirmed that Roxy had an alibi for the time of Roganâ€™s death. Theyâ€™re writing it off as a suicide. Pete lets MacGyver know that Roxyâ€™s doctor has agreed to meet with him. MacGyver goes to see Roxy, who doesnâ€™t believe that Rogan would kill himself. She suspects that Carla killed Rogan and tried to frame her. However, she refuses to go to the police without any evidence. She does admit that Carla had a key, and that she never changed the locks because she hoped that one day the sisters would reconcile their differences. Roxy remembers high school and how she always loved MacGyverâ€™s smile. MacGyver is skeptical of Roxyâ€™s claims, and notes that the sisters were fiercely protective of each other in high school. Roxy will only say that things changed and that Carla killed Rogan because he and Roxy were once lovers. Now Roxy believes that Carla will go after MacGyver next.
At the psychiatric hospital, MacGyver talks to Roxyâ€™s former doctor, Farrell. He talks about how his patient was there and how her twin sister visited her regularly. However, he then says that Carla was the one who had the breakdown and Roxy was the one who visited.
MacGyver goes back to Carlaâ€™s house. He examines the paintings and finds one that shows Roxy and Carla climbing together. It shows Roxy hanging from a rope fastened to Carla, who is holding onto a rock. Using a telephoto lens, MacGyver magnifies the image and sees that in the painting, Roxy is cutting the rope. Finally, MacGyver uses some paint powder to take a fingerprint from one of Carlaâ€™s jars.
Roxy is filming at a secondary stage as Pete and Eve look on. Once they finish, Roxy sees a woman who resembles Carla. She chases after her to the main studio and comes face-to-face with a dressing room mirror. Confused, Roxy stares into the mirror and addresses her image as â€œCarla.â€
MacGyver returns and tries to find Roxy. He and Pete go to Roxyâ€™s trailer and take a fingerprint from her hand mirror. They compare the two fingerprints, Carlaâ€™s and Roxyâ€™s, and discover that theyâ€™re identical. Pete calls Farrell while MacGyver goes to find Roxy in the main studio. He sees Carla up above and, and she tells him that Roxy isnâ€™t there. MacGyver approaches her, explaining that â€œRoxyâ€ isnâ€™t there. Carla had her breakdown, and later went rock climbing with Roxy. Roxy slipped and cut herself free rather than take Carla with her. Carla had another breakdown and tried to keep Roxy alive by impersonating her. Both Rogan and Eve noticed that she wasnâ€™t quite herself.
MacGyver tries to comfort Carla, but she insists that Roxy is still alive. She grabs a wrench and knocks him out, and then ties him up in a straitjacket from the video and drops him into a water tank. She goes to get a gun while MacGyver uses the air from the bubble generator to keep himself alive long enough to cut himself free on an underwater spotlight. He goes to get Carla, who is preparing to shoot herself so that no one can hurt â€œRoxyâ€ ever again. MacGyver tries to get through to her and persuades her that it wasnâ€™t her fault that Roxy died. Carla puts the gun down, crying, and MacGyver tells her that she can let Roxy go.
Later, Carla returns to Pine Valley for further treatment. MacGyver goes to see her and she thanks him for everything heâ€™s done for her. She asks for one last smile from him before being led away. Farrell tells MacGyver that sheâ€™ll get better, but itâ€™ll take time and if MacGyver would visit her, it would help.