Part 1 of 2. In the Season 3 premiere, it's months after Peter's death and Megan returns to work, only to learn she's been teamed with a detective with whom she has a past history. She, Det. Sullivan and his rookie partner are up against a serial killer who targets young war veterans. The stakes become higher after she gets a call from the killer and is told he's holding her teenage daughter, Lacey, hostage.

In conclusion of the two-part Season 3 premiere, Megan discovers why the serial killer targeted war veterans, but must keep the information to herself or risk the life of her daughter, who is being held hostage by the assassin. Meanwhile, District Attorney Dan Russell has a run-in with Kate.