A classic murder mystery by acclaimed crime writer Bernard Knight. When super-rich Margaret Walker is found dead after a wild party, people assume it was an overdose - until a knife wound, almost invisible, is discovered on her body. But who would have wanted to murder her? As the investigation progresses, it is discovered that some of the party guests may have had a motive to kill Margaret...but were those motives enough to make someone a murderer - or was it a case of mistaken identity?