A transferred detective constable, De Pauli, joins the vice squad when they are in the midst of a struggle with criminals that team members grew up with.

Callaghan and De Pauli look for a young girl who has gone missing; Frank "Mad Dog" Gagliano seeks vengeance against Callaghan.

Callaghan and De Pauli interview a pedophile connected a case involving a young boy who has disappeared; Callaghan learns that a local drug baron has invested money in his brother's new bar.

De Pauli investigates a violent case, drawing him into John Sullivan's past; De Pauli and Callaghan investigate a stabbing at one of Sullivan's clubs.

Callaghan and De Pauli have their private lives dragged into the station while they try to investigate the murder of a prostitute; Will tells De Pauli that he quit his job.

Night surveillance gets complicated when De Pauli gets stuck in a shop with the people they are supposed to be watching.