Following Wozniak's discovery that Stahl's target is his close friend and Mayoral Candidate, Julia Ayers, Wozniak launches an all-out war with Stahl. Meanwhile, Harlee dives into an investigation that takes an unexpected turn into her own past - and ultimately throws her in the cross-hairs of Wozniak and the FBI. At the precinct, a new, unwelcome presence threatens to uncover the crew's deepest secrets.