After 21 years, sex offender Ray Schenkel is released from jail. Retired officer William Dorsey who initially locked him up, is convinced he'll offend again and begs Detectives Benson and Stabler to put him away for good. Stabler goes undercover to see if Dorsey is correct and in doing so befriends Schenkel, posing as a sex offender on parole and earning his trust. As the investigation unfolds, Stabler sets Schenkel up, but this time he doesn't take the bait. When Stabler's cover is blown, the investigation is not only compromised, but Stabler finds his life in danger.