MacGyver’s rock star friend Roxy Yates is filming an anti-drug rock video for the Phoenix Foundation in Chicago. Pete and MacGyver visit the set during production. Once she finishes, the director Eve complains that Roxy is sexing it up too much and orders another take. Roxy complains about Eve, who berates her again. The rock star walks off the set and Eve tells Pete to fire Roxy if he wants a decent video, because Roxy has lost something. The set closes down and MacGyver goes to talk to Roxy.
At her trailer, Roxy complains to her manager, Frank Rogan, that he's stealing royalty money from him. Frank insists he has expenses to meet and that Roxy isn't what she was once. She orders him out, warning him that she plans to call the D.A. and provide him with the evidence he needs to convict Rogan. MacGyver arrives as Rogan threatens Roxy. Once the manager is gone, Roxy and MacGyver discuss their childhood together and her twin sister Carly. Roxy says that Carly's doing fine. MacGyver tries to convince her to come back to the set and Roxy agrees to show up for work tomorrow. She asks him to give her a lift home so she can show him her place. As they take the express elevator to her hotel penthouse, Roxy asks him to dinner in return for her help. The elevator stops and the phone is dead. The cables slip and MacGyver climbs up top. He discovers the cable mounts are loose and are slipping fast. He gets Roxy up and they grab the pipes just as the car plummets down the shaft. All the doors are bolted and they have to free-climb up the shaft. Roxy easily makes the climb. They get to the penthouse door and MacGyver manages to get the door open, getting them to safety. Inside Roxy's penthouse, MacGyver wonders if Rogan was made enough to sabotage the elevator. Roxy says that her sister Carly tried to kill her.
Later, MacGyver goes to see Carly at her lakefront house. He notices that she's doing paintings of mountains she rock climbed with Roxy. Carla admits that Roxy hasn't practiced her rock climbing recently. MacGyver brings up Roxy's accusations and Carly says that Roxy has had several other "accidents" recently. Carly dismisses Roxy's accusation and says that her twin sister had a breakdown and spent a year at Pine Valley Hospital.
MacGyver returns to the studio and sees Rogan just leaving Roxy's trailer. Pete comes over just as Roxy arrives. She figures that Rogan is looking for the evidence she has against him. Roxy then accuses MacGyver of not believing in her, and claims that Carly called and gloated to her over the phone. She thinks it's a matter of sibling jealousy and Carly is fixating on MacGyver now that he's come back into Roxy's life. Roxy warns him not to turn against her too. They go in to start filming and everything seems to go well. Eve congratulates Roxy as MacGyver tells Pete about the problems between the two sisters. He asks Pete to talk to the people at Pine Valley
Rogan goes to Roxy's penthouse and she invites him in. He thanks her for dropping the charges against him. From the next room, Roxy tells him to go look at the papers out on the terrace. Rogan goes out to check them... and Carly comes out behind him and throws him over the balcony to his death.
Pete and MacGyver arrive at the crime scene after the police finish interrogating Roxy. They wonder how Rogan got in and the police suspect that Rogan broke in, drunk, and committed suicide when he realized he was going to be prosecuted. Roxy was down at the health club doing her morning routine when Rogan died. Pete assures MacGyver that he can meet with the Pine Valley doctor. MacGyver goes upstairs to meet with Roxy, who insists that Rogan wouldn't have committed suicide. She accuses Carly of killing Rogan but admits she didn't tell the police because she has no evidence to back up her claim. Roxy admits that Carly had a key. She talks about the fun they had together in high school and admires MacGyver's smile. MacGyver wonders why Carly would try to hurt Roxy after their teenage years when they protected each other. Roxy says that things have changed and that Carly killed Rogan because he and Roxy were once lovers. Now Carly is going after everyone who was ever close to her.
MacGyver goes to Pine Valley to talk to Dr. Farrell. He remembers the breakdown and how her sister always came to visit. However, he reveals that Carly was the one who had the breakdown and Roxy was the one who visited. MacGyver goes to Carly's house and discovers she's gone. He sees a camera and uses the telephoto lens to blow up an image of the two sisters rock-climbing. He realizes that the painting shows Roxy hanging from a line and cutting herself free with a knife. Using paint powder, MacGyver lifts a fingerprint from a brush jar.
Eve is filming a blue-screen session with Roxy. Once they're done filming, Pete thanks Roxy for her help. Roxy spots a woman, apparently Carla, walking off the set and goes after her. The woman ducks into the video's main studio and Roxy goes in to find her. Roxy spots a dressing room mirror and stares at her reflection, then starts having a conversation with "Carla."
MacGyver arrives and Pete admits he doesn't know where Roxy is. They go to her trailer and MacGyver lifts a fingerprint from her hand mirror. As Pete looks on, MacGyver realizes that the two fingerprints are a match. Pete calls Dr. Farrell while MacGyver goes to the studio to find Roxy. Carla comes out and tells him that Roxy isn't there. MacGyver explains to her that "Roxy" went away. He explains that Eve and Rogan both noticed that "Roxy" didn't sing the way she used to, and that "Roxy" wasn't that good a climber. MacGyver notes that in the painting, he could see Roxy cut herself free so that she wouldn't take Carla with her. Carla talks of how she tried to help Roxy but she couldn't pull her up in time. Carla insists that Roxy isn't dead as MacGyver embraces her. She grabs a wrench and hits MacGyver, insisting she won't let him kill him. She puts him in a straitjacket from the set and throws him into the studio's water tank.
As Carla puts on Roxy's dress and takes a gun from her purse, MacGyver manages to get some air from a prop hose providing bubbles. He then hooks the straitjacket strap on a broken floodlight and cuts himself free. Meanwhile, Carla loads the gun and insists she won't let anyone hurt "Roxy" ever again. She prepares to shoot herself but MacGyver arrives and tries to assure her it wasn't her fault that Roxy died. Carla puts the gun down and breaks down, crying. MacGyver realizes that Carla brought Roxy back the only way she could. He tells Carla to let Roxy go and she finally accepts that Roxy is dead and that it was an accident.
Later, Carla is at Pine Valley again and MacGyver comes to visit. She thanks him for his help and he tells her to take care of herself. She asks for one last smile and promises to always remember it before the nurse leads her away. Farrell warns MacGyver that it will take a lot of work and it would help if MacGyver visits from time to time.