Whilst Doyle is on a date with Kathie Mason his flat is robbed and a powerful laser gun which he was given to test is stolen. After an attempt to kill him, he and Bodie make inquiries as to who would have stolen the gun and Maurice, one of their informants, is shot dead with it. Another colleague is taken prisoner as bait to flush Doyle out in the open by the thief, Preston, a disgraced ex-cop sent to prison on Doyle's evidence and now after revenge. But who knew Doyle's routine that well that he - or she - was able to tell Preston about the gun?