When the body of Sir William Ponson is found in the Cranshaw River near his home of Luce Manor, it is assumed to be an accident - until the evidence points to murder. Inspector Tanner of Scotland Yard discovers that those who would benefit most from Sir William's death seem to have unbreakable alibis, and a mysterious fifth man whose footprints were found at the crime scene is nowhere to be found...

First published in 1921, this was Crofts' second book after his masterpiece debut "The Cask" and is another early classic from this Golden Age master of mystery and suspense.