 When murder is committed on the good ship Susan B Jennings, Charlie has just left home, Chan s young son Tommy takes the telephone call at when Charlie is called in on the case. Tommy tries to run out to catch his Dad before he can drive away, but he is stopped by elder brother Jimmy, who wants to be a detective himself. Jimmy takes the call, and goes out to the ship himself, where he introduces himself as his father. He proceeds to take over the case. In a brilliantly funny comedy of errors, Charlie finally finds out that he s supposed to be on the  Jennings  and travels out to the harbor, where he straightens things out and begins to investigate. Among other characters is a doctor who keep a living human brain in a suitcase in order to be able to continue his experiments on it, another police detective who is taking in a prisoner, and who seems oddly interested in Chan s case, and a disreputable looking fellow who is escorting a pet lion. $300,000 have been stolen, another person is murdered, and the Captain of the liner is putting pressure on the Honolulu Police Department to let him take the ship out of the harbor and get on its way before the shipping company loses too much money. Can Charley solve the crimes before his chief forces him to give up on the case and let the Captain make way?