As the team searches for a vigilante killer in Cleveland, Rossi's former Marine sergeant goes missing in Los Angeles and J.J.'s secret catches up with her.
Melinda tries to persuade the mayor to cancel the memorial, and searches for missing children with Professor Payne.
Lily and the team re-open a 1976 case concerning the murder of a 17-year-old girl when new evidence surfaces. Whilst piecing together the decades-old puzzle, a telling photograph indicates that the victim had connections to a notorious motorcycle gang. Does a biker have blood on his hands?
Hannah has a hit song with Austin Rain. On screen it looks like they get on well. In fact they can't stand each other. Hannah owns up on TV, to persuade Jackson not to cheat in an exam.