Catherine's father is murdered and the team must help her find the killer. Yet Steve begins to recognize the angry signs of vengeance stirring in his girlfriend's eyes, and he struggles to help her work through the case, and protect her from the lack of objectivity he knows from experience comes from losing someone close. It is his case to run, and she is his to protect.

Steve and Catherine clash when despite being pregnant she wants to take part in a case. In true McRollins fashion, it takes a dangerous situation and a trip to hospital to make them consider the others opinion.

After an incident at a charity triathlon, Steve and Catherine get some exciting news, one they then have to share with anxious friends and family.

When a serial killer seems to be counting down victims who are military, Steve and the team struggle to piece together the nuzzle when one of their own is taken. Will they save Catherine in time? Or will she be another tally on the killers list?

When Catherine is framed for the murder of the governor's son at a charity auction the team will do everything they can to see the story set straight. Yet her and Steve's actions soon put obstacles in the way, and with her prints on the gun, and a new head of HPD out to land himself a killer case quickly, what can they do?