4. Hard Cases

'If I hear the music, I'm gonna dance.' -- Greggs Sobotka reprimands his nephew Nick for stealing the cameras and orders him to bring the cargo back--too late. McNulty is on a self-assigned moral mission to identify his floater, but his old partner, Bunk, says they have a more pressing matter at hand: to find Omar so he can testify against a Barksdale trigger man in one of last year's murders.