Masters goes undercover in Stonewall private prison in an attempt to eradicate the ongoing problem of drugs getting onto the wing. However, she soon faces opposition from a less than co-operative colleague, Pete Mason, who she believes is harbouring one of the main dealers, Cherry Watkins. Masters uses Lesley Palmer to gather information on one of the more vulnerable inmates, in the hope that she can provide a vital lead. Meanwhile, Nixon investigates the shooting of a young girl on the Ellis estate. The gun used in the shooting is linked to another attack just two months ago, but the situation becomes complicated when the victim is found in possession of live ammunition. (thetvdb.com)