A vigilante killer is on the loose in Cleveland, JJ's secret finally catches up with her, and Rossi is on the search for his missing Marine sergeant.
Melinda tries to persuade the mayor to cancel the memorial, and searches for missing children with Professor Payne.
A new-found photo of a murdered 17-year-old on the back of a motorcycle, indicates her connection to a notorious gang, and prompts the team to reopen the 1976 case.
Hannah is not on good terms with celebrity Austin Rain, despite having a hit song together; Hannah tries to persuade Jackson not to cheat in an exam.