A convicted rapist, Ray Schenkel, is released after 20 years. When rapes of young girls immediately start occuring, the now retired, arresting officer gets it in Stabler's head that Ray is the rapist. Stabler decides to do surveillance on Ray and follows him to his Parole Officer visit. Stabler goes undercover and poses as a former sex offender to get into Ray's group therapy classes. Cragen is reluctant to let Stabler do this considering there is a 50/50 chance this guy may be a changed man. While undercover, Stabler comes face to face with a darker side of himself and the possibility that Ray may be a changed man.