The mightily appealing hero of this crisp, low-key British mystery is Harry Somers--a bouncer/bodyguard with a prison record (""only a little one"") who reluctantly, fearfully takes over the Coronet Private Investigation Agency when his boss there keels over dead from a heart attack. Harry's first case is a tough one. The client is former crook Phil Holliday, who was part of a secret gang that pulled off a huge robbery eight years ago; now, it seems, an anonymous blackmailer is threatening to unmask the never-apprehended robbers--one of whom has recently turned up dead (presumably murdered by the blackmailer). So Harry's job is to finger the blackmailer--who just might be one of the six surviving gang members. But, as you might expect, the ex-robbers (now in new walks of life) aren't eager to chat with Harry about their old crime. And it's only after quite a few uneasy confrontations--and one or two violent showdowns--that fledgling shamus Harry (encouraged by firm secretary Yvonne) comes up with a neat two-part solution for the blackmail/murder mayhem. Significantly enriched by rough, old-fashioned Harry's courtship (comic, touching) of a sophisticated, liberated schoolteacher: sturdy entertainment in a wry, medium-boiled British (East End) vein.