Jaime is being pursued by Warden Cooper, policemen, helicopters, and dogs, after escaping from the prison she was brought to and switched with her evil double, Lisa Galloway. She also falls into a quicksand trap. However, she gets away from it all with her bionics.
Oscar is not pleased to hear that 'Lisa Galloway' got away. Cooper, who has been led to believe by Lisa's prison accomplices that Lisa has gone insane and believes she is Jaime Sommers, now tells Oscar this as well.
Meanwhile, Lisa delivers only a quarter of the adrenalizine the OSI gave her for the Federal Labs. She was contracted to take the rest to her boss, Dr Courtney. But she decides that she likes living Jaime's life so much (and does not know about Jaime's escape) that she is going to carry on living that life forever and keep the adrenalizine for herself. She tells Courtney this, and does not listen his warning that she will be soon be discovered or his pleas to accept her $10 million fee and come with him. She is soon heading back to Ojai to live with Jaime's family.
But before long, Lisa's new-found happiness is being punctured by inexplicable stomach pains. She is also beginning to lose her grip on her identity for real, and is constantly nibbling at the adrenalizine, even when she has no use for the bionic-like power it gives her.
Jaime makes her way to a storage depot, where she calls Oscar for help and explains what happened. But Oscar, after hearing the piece of misinformation from Cooper, feigns sending help while in fact informing Jaime's pursuers about her location.
Cooper soon has Jaime cornered in the depot where she has barricaded herself in bionically. They use harsh tactics, including shooting out a window, to force her to surrender. She persuades them to get Oscar, using Woody, the depot attendant as her 'hostage.' Woody agreed to this after seeing Jaime's bionics in action. When Oscar arrives, Jaime finally convinces him of her identity by having him whisper a question to her, which she can answer because she can hear it bionically.
Courtney's accomplices, Dr Harkens and Weber, are arrested and confess to being on his payroll. This informs Oscar of Courtney's involvement; he did not even know Courtney had escaped from prison because nobody told him. Cooper can only apologize to Jaime.
Back at the OSI Jaime is introduced to Plato, the adrenalizine test rat, while Oscar discovers how much adrenalizine Lisa has stolen. Lisa then betrays Courtney entirely by sending an anonymous tip to the OSI about his whereabouts. Jaime joins Oscar and Rudy in heading off to recapture him.
As they head off, none of them notice that Plato is acting strangely; he is writhing about in his cage as if in great pain.
When they catch up with Courtney, he mistakenly assumes Jaime is Lisa. He angrily informs them what Lisa has done, and, not knowing Jaime has escaped, tells them that the real Jaime is in a prison grave wearing Lisa Galloway's face – confession! As he is taken away, he sneers at 'Lisa' for seriously thinking she can actually live out her life as Jaime.
A call to Helen confirms that Lisa has indeed returned to Ojai. Helen also expresses deep worry, for Lisa's stomach pains have worsened. Helen is instructed to keep a quiet eye on Lisa until they arrive.
As Jaime and Oscar head off, Rudy bursts in with the now-dead Plato. He informs them that the adrenalizine is breaking down chemically and turning poisonous; if they do not get to Ojai fast, the adrenalizine will kill Lisa as it has killed Plato. He also warns them that if Plato's last hour has anything to go by, Lisa may be experiencing severe and dangerous mental problems.
When they arrive, Jaime decides to heed Helen's urging to go in for a one-to-one approach with Lisa, especially after the treatment she experienced at the depot. Oscar is reluctant to allow it, but does so. However, this approach is not easy because Lisa is now increasingly insane, in great pain, believing she really is Jaime Sommers, and moaning at how she does not want to be Lisa anymore because nobody loves her. Worst of all, she is still dangerously full of adrenalizine strength, as exhibited by the objects she throws at Jaime, who has to deflect them bionically. But in the end Jaime gets through, and Lisa meekly surrenders at her feet.
Lisa recovers in hospital and finishes the tapestry Jaime was working on just before Courtney kidnapped her. She is now willing to take its motto, "To Your Own Self Be True" on board and undergo the surgery to restore her proper face, because she has repented and apologizes to Jaime. She and Jaime make up.