There is great consternation at Sir Henry Swatham's mansion when his wife, Lady Marion, discovers a naked young woman in their library. Bound to a heavy mahogany desk with a ball gag in her mouth, her bottom is sporting ten evenly spaced stripes - clearly the result of a recent caning!

Lady Marion wastes no time in summoning Detective-Inspector Trevath who quickly arrives at the scene accompanied by the local doctor. The inspector puts his keen mind to work and, having discovered a number of canes at the scene of the crime, is able to identify which one has been used in the assault by applying each one to the bottom of the victim.

After some further deliberation, Trevath is able to solve the case and the guilty party is unmasked. It looks like a great deal of scandal and a lengthy prison sentence awaits the culprit but when a 24-stroke caning is offered as an alternative punishment it is reluctantly accepted by the perpetrator.