Jo and Gary continue the investigation into dealer Bernie Cryan, and find that a young lad from the local estate, who may be one of Cryan's dealers, may finally be their way in to nail him. However, Laura, having known the boy and his mother in the past, finds a totally different angle on the investigation. Meanwhile, Terry's pursuit of Margaret Barnes leaves him in grave danger when Margaret's attempt to commit suicide leads to him receiving a critical stab wound. When Margaret turns up at the station, Ramani tries to find out exactly what has happened. Tony and Dan try to track down an inventive graffiti artist who uses cleaning products to produce negative images on dirty walls. (thetvdb.com)