World-famous detective Charlie Chan (Warner Oland) joins the circus to expose a killer in this breathtaking (Motion Picture Herald) three-ring murder mystery! When the esteemed detective takes his honorable wife and all twelve children on an outing to the circus, he soon discovers that the main attraction is a baffling case of murder. And with a rampaging gorilla on the loose, his overzealous Number One Son (Keye Luke) on his heels, and everyone from the snake-charmer to the contortionist a suspect, Chan must walk a tightrope of terror to unmask the murderer... before disaster strikes again!