On his return from India, Commander Joe Sandilands, now adept at the arts of dynamic diplomacy, finds himself up to his neck in a tricky political situation. A war-weary London is reeling from IRA atrocities and Joe is further plagued by the machinations of a spy-ring being run under his nose by a Russian emigree princess. When a war hero is gunned down and the life of an even more popular Englishman threatened, Joe knows he only has days to root out the woman who is behind the killings: Irish? Russian? Or somebody quite other? With the aid of the proposed victim who offers himself as bait, and the services of a woman police constable, Joe discovers that the murderer's motive is not political but much more devious and deranged. And when the mask comes off, the killer's identity shocks even the battle-hardened commander.