When the body of what appears to be a city gent, complete with pinstripe suit, umbrella, briefcase and bowler hat, is discovered buried in the sand of a holiday beach, the lugubrious Inspector Buckett and the keen but hapless Sergeant Spade are sent to investigate. It transpires that the briefcase contains a gun and 25 thousand pounds and that the deceased has the initials FM tattooed on his buttocks. The case taxes all of Buckett's investigative powers as each lead they follow seems to direct them down a blind alley. On route to the riddle's final and bizarre solution, they encounter a gallery of larger than life characters; Mr and Mrs boring suburban couple, a Saville Row tailor and his raucous cockney cutter, and the upper crust Sir Frank Morton QC and his Scottish wife. And in the end the solution is all to do with monkeys and typewriters.