A narcotics officer goes undercover with the Jump Street crew to help bust a drug dealer. Penhall develops feelings for her, but problems arise when she is suspected of being addicted herself.

Doug Penhall's estranged brother, Joey, transfers to the Jump Street Unit. After his attempts at making amends with Doug are rejected, he takes an assignment in which he must go deep undercover in a religious cult in order to extract a man's daughter and to prove that the cult is involved in illegal activities.