A boxer is killed in the ring, and the only clue is a tune that a man was whistling.

Neil Hamilton
as Bill Devons

Evelyn Venable
as Pauline Ward

Jimmy Wallington
as Nick Nicholls

Barbara Pepper
as Althea Ames

Lucien Littlefield
as Watchman

Lynne Roberts
as Edna Mayberry (as Lynn Roberts)

James Spottswood
as Albert 'Slats' Keefe

Reed Hadley
as Ralph Mortimer

Robert Homans
as Captain Joseph Filsom

William Haade
as Tommy Madison - the Champ