Simone and Sipowicz investigate a claim of sexual assault against a mentally disabled 17-year-old schoolgirl, after her domineering and verbally abusive mother reports it. They try to persuade her to press charges against the two assailants. The alleged assailants are from privileged backgrounds who attend an exclusive prep school. One is the son of sleazy councilman Paul Manos, with whom the detectives had problems a year earlier. Meanwhile, a young man who speaks only gibberish, known to Sipowicz who had him committed four years ago, appears at the station and causes a minor scene -- trying to get someone to listen to him about a problem he now has. Sipowicz investigates. Meanwhile, Russell continues her undercover work and relationship with Jimmy, who shows off his true psychopathology when he beats up a roller blader who had accidentally bumped into Russell.

Simone and Sipowicz investigate a story that a diamond dealer and his partner report that one of the dealer's sisters is missing with a bag of diamonds worth a million dollars, but the sister's boyfriend is actually responsible. Meanwhile, Martinez, Medavoy and Russell look for the assailant of Gina who badly slashed her face up while she was on her way to work, and Martinez cannot cope with this sudden turn of events. Simone and Kirkendall go out on their first date, while Russell cannot cope with the fact of being alone again.