Erin reopens an 18-year-old rape case in which Frank was the arresting officer. Meanwhile, Danny and Jackie investigate the murder of three teenagers in a park who seemed to have been killed for no reason.
Only one of three teenage schoolmates survives an apparently unprovoked shooting in a park. Danny has a hard time identifying suspects and working out a motive. Modern DNA tests prove that a man whom Frank Reagan arrested 18 years ago as serial rapist was actually innocent. Despite the statute of limitations, the hunt for the real perpetrator is started.—KGF Vissers