A body plunging off a cliff, a new craze for pedestrianism and the related gambling, a constable willing to walk ninety miles without stopping, and a testing undercover assignment for Mr. Hardy.

When a race walking champion is forced off a cliff to his death, and his fellow race-walkers are all suspects, Mr. Hardy and Constable Foster go undercover to find the killer. An accident-filled race leads to a showdown in the bubbling mud and geysers of central New Zealand.

The Mr. Hardy Investigates series is spun off from The Sergeant Frank Hardy Mysteries.