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.

Disturbing 911 call from nine-year-old Maria Recinos is forwarded to Detective Olivia Benson. Recinos is calling for help from a room she claims to have been locked in for days. The detectives put a trace on the cell phone she is using, however it turns up multiple phony leads due to manipulation of the signal, which leaves detectives confused. As the case progresses, Benson eventually convinces Recinos to divulge crucial clues, including the name of her captor. Recinos will only talk to Benson, and just as she is getting closer to finding her, the cops question the case and are now concerned that it could be a prank. Benson knows this is real, when the phone goes dead, Benson realizes that she is losing time and needs to act quickly on what little information she has if she is going to save this girl's life.