DI Robbie Ross starts to feel the heat when Thomas Duffy, one of his informants, is brutally murdered, and the word 'grass' daubed in paint at the crime scene. Duffy's name appeared in Ross's contact book - which was stolen by a woman Ross took home with him. Ross knows he must speak up, but before he does, another name from the book turns up dead. Can he solve the case before his career becomes the next casualty?