Twenty years after being convicted of the rape of a teenage girl, Ray Schenkel is released, much to the dismay of retired detective William Dorsey. When a teenage girl is raped on the route Schenkel would have taken home, Stabler goes undercover as a recently paroled sex offender so that he can get into the same therapy group as Schenkel, and the same halfway house. Cragen worries that Stabler may be getting in over his head.