Ruth Winton, author of The Great Diamond Mystery, tests its hypothesis--that a murderer will return to the scene of the crime--when her sweetheart, Perry Standish, is sentenced to death for the murder of his employer, Graves, a diamond merchant with underworld connections. Ruth rents Graves's house; rehires Davis, the butler; and notices that Mallison, Graves's partner, snoops around the house for some missing diamonds. In the climax, the butler is shot and makes a dying confession to Graves's murder; Perry is pardoned at the last minute.—AFI