While building a racketeering case against construction contractors and union leaders, Erin is devastated to learn Ray Milo, her informant, is murdered by a hitman. As she speculates who outed him as a whistleblower and wanted him dead, Danny and Jackie investigate the two most likely suspects: a vengeful contractor, and a corrupt union leader who Milo planned to wiretap. After the hitman is arrested, Danny coerces him into revealing his employer is the contractor, who learned of Milo’s whistleblowing from the woman he was having an affair with: Milo's wife. Meanwhile, Frank faces a media hailstorm after video surfaces online showing a NYPD officer assaulting an old man. But after obtaining the original, unedited video from the journalist who leaked it, Frank realizes the cop acted professionally and stands by the man's actions.