After the badly beaten body of a man is found dumped on a motorway underpass, his murder is linked to a Fight Club style bare-knuckle boxing venue. Both professional and personal lives collide at Maryhill CID, with one of the detectives having to come face to face with their own demons.

When a busker is fatally stabbed in Glasgow city centre, the newly promoted DI Jackie Reid heads up the investigation. Mita Rahim joins the Maryhill CID team properly while DI Ross suffers a personal heartache.