Inspector Lynley and Detective Sergeant Havers are assigned to a new case back in London, following the discovery of a body floating in the Thames. The victim, Eric Ramsey, was a doorkeeper at the House of Lords. On closer inspection, it appears that he has been savagely beaten, having had his hands tied behind his back. Initially, it looks as if the murder may be connected to Ramsey's gambling debts, but when a Clerk at the House of Lords is also murdered, events seem to point to a wider conspiracy involving stolen documents. Havers sets to work tracing the missing documents, which turn out to be a test report on a missile system. The detectives suspect that the murders may have been carried out by whoever was looking for the missing report. But they soon realise that they themselves are being followed. Who would benefit from the suppression of the test report? Is it that person who is having Lynley and Havers followed? And will they be able to get to the killer before someone else gets to him? Meanwhile, Havers goes to a singles night in an attempt to establish a life for herself outside work.