When a severed hand is discovered at the scene of a drug bust, the team re-opens the 1997 case of a convicted criminal who was thought to be on the run from authorities all these years.

A drug addict mother, who lost her son in an apartment fire in 2005, comes forth claiming she just saw the same child in the park.

The 2004 murder of a teen at a juvenile detention center is investigated. The boy was wrongly sent to the facility and was killed before Valens could get him released. Meanwhile, Lilly reconnects with former flame Eddie Saccardo, a narcotics officer.

The 1991 murder of a 14-year-old girl in foster care who was a promising rapper is investigated. The probe reveals the victim lived in a gang-infested neighbourhood and was recently placed, along with her sister, with new foster parents.

The 1983 murder of a Chinese-American teen is reinvestigated. The case was originally handled by Stillman. The probe reveals the victim's girlfriend was killed by Chinese gang members three months earlier at a festival and that the dead man may have been seeking revenge.