During the unloading of an Insular and Continental Steam Navigation Company ship arrived from Rouen, the Bullfinch , a cask falls, splits, and reveals its unexpected contents. As the dockworkers try to work out what to do, Mr. Léon Felix arrives and claims the cask as his own. His actions set into motion a complicated trail for the detectives of London’s Scotland Yard and Paris’s Sûreté to follow to the end.

Freeman Wills Crofts was one of many authors writing crime fiction in Britain in the 1920s and 30s, and was a contemporary and acquaintance of both Agatha Christie and Raymond Chandler. The Cask , his first novel, was written during leave from his job as a railway engineer, but its reception was good enough to set Crofts on the course of a further thirty crime novels over his career as an author.