Sir Basil Riordan-mysterious, frightening, an immensely wealthy. Was he also a killer? As head of England's elite secret service, " Z " Department, Gordon Craigie had to find out. It wasn't an easy investigation. Too many important people were involved. A member of an exclusive London Club was poisoned. Could Riordan or his son, Marcus, be involved? It looked that way. So Craigie assigned his best agent, Devenish, to the case. What Devenish, found was no clear-cut case of homicide. Instead it was a mad masquerade of murder, larceny, and deceit of the highest order and send Craig himself was in over his head.