The driver in a robbery reveals himself to be an undercover FBI agent named Castillo, and he arrests the criminal who killed his partner. Meanwhile, at the training center for the California Highway Patrol, an older rookie motorcycle officer named Jon Baker is being allowed to graduate on a probationary basis. He is a former freestyle motocross racer beginning a new career after his body has been left damaged by his sport. He is on a regimen of pain killers and is living in the guest house, after he and his wife separated when he lost his sponsors. The FBI agent, now undercover as Frank (Ponch) Poncherello, is sent to the CHP after an armored car robbery, which makes it apparent that there are corrupt cops working in the department. He is partnered with the rookie Baker, who will be too inexperienced to understand the corruption investigation Ponch will be leading. The corrupt officers are seen being led by Lt. Ray Kurtz, who is stealing the money from armored cars to get his heroin-addicted son out of Los Angeles. Ponch argues with his new partner over whether Baker's wife is unfaithful, while Baker gives Ponch unsolicited advice on what he perceives to be a sex addiction. Ponch is fired from the FBI when he ruins the investigation of another agent in which a suspect is killed. However, he is sworn into the CHP when he and Baker identify the dead suspect as Ray Kurtz' son. Kurtz sets a trap for them by kidnapping Baker's wife. Baker knows it is a trap but persuades Ponch to go anyway, despite the fact that his wife has just sold their home without his approval. After successfully rounding up the gang of corrupt officers and killing Kurtz, Ponch decides to remain in the CHP.