Andy is worried that her personal problems are clouding her professional judgment when a woman is brutally attacked on her watch. Detective Luke Callaghan is convinced that it's the same suspect when the details of assault are alarmingly similar to the unsolved murder of a rookie. Ironically, Andy is caught in between dueling theories of the crimes—one supported by Luke, the other by Jo Rosati. But when Luke is booted from the investigation because of erratic behavior, he tries to get Andy to follow through on his hunch—putting her in serious danger.

It's a race against the clock as Dov and Gail work under Swarek's expert tutelage in a stakeout operation to stop an Asian gang from killing a snitch. Meanwhile, at Mounted Unit training day, Andy and Chris join the rookies from 27 Division in a competitive equine training event that gets Andy back in the saddle—both personally and professionally.