It's 1946 and private detective Mason T. Adler isn't thrilled to be turning fifty. The party Walter Waverly Wingate throws him makes him even more uncomfortable. Walter has arranged a special birthday present for Mason: a private hour with the handsome, young Henry Bowtrickle in Walter's upstairs bedroom. But the night turns deadly when his birthday gift turns up murdered. The room was locked, no way in or out, and only Henry and Mason were inside. Mason Adler is on the case, but he is also a suspect, along with the other assorted party guests who were all downstairs at the time of the stabbing. Or were they?