While steaming from Honolulu to Los Angeles the owner of a prize racehorse headed for the Santa Anita Handicap is killed, apparently kicked to death by his stallion. Not so, deduces Charlie. Leter he exposes efforts to fix a race at the famous track.

While ostensibly on vacation with his wife and twelve children, famed detective Charlie Chan visits a circus at just the right time to become involved in the murder of one of the circus owners. Chan is prevailed upon to travel with the circus in hopes of discovering the killer before he, she - or it - strikes again.