On a sultry afternoon in July, a man stumbles through thick foliage and rough ground, making for the coast. He wears prisoner's garb and the guards are hot on his heels. Happening upon a bather's clothes – the bather nowhere in sight – the escapee takes the risk, changes and leaves the scene looking the part of the average beachcomber.

But it can be hard to stay hidden forever. When a blackmailer intrudes for the last time upon the promising life of the man who now calls himself Mr. Pottermack, a violent fate befalls him, and the stakes are set: Pottermack must avoid discovery at all costs to escape the hangman's noose for murder. 

When Pottermack's attempts to tamper with the evidence arouse the suspicions of the fiercely forensic Dr. Thorndyke, the cat and mouse game is afoot as we follow both detective and suspect in their battle to root out – or bury – the damning truth in this inverted-mystery classic first published in 1930.