While investigating the murder of a man who killed a mother and son years earlier while driving drunk, Danny and Baez are torn between doing their job and finding justice after discovering the connection between the suspect and the victim. Also, Anthony is conflicted when Erin asks him to wear a wire to incriminate his old friend who is involved with the Russian mob.

Jamie and Eddie suspect foul play when they respond to a distress call from a woman having an allergic reaction to her lifesaving medication, and learn that her husband is an EMT assigned to take her call, but didn't respond. Also, Erin learns that a man she convicted years earlier might be innocent of the crime, and Frank handles a PR crisis in his department when an exposé on Garrett Moore is published.