The police arrest a man climbing over the wall of a cemetery after midnight. He claims that he is being blackmailed and is following instructions he received by mail to leave $1000 on a certain grave. It turns out that he's not the only one who got a blackmail letter from the same person--calling himself "The Black Panther"--and it also turns out that all the recipients are connected to an opera company.

Movie actress Linda Winters has gone into the jungle to find her lost husband Fred. Bomba the Jungle Boy helps in the rescue effort. A major obstacle facing them is a killer leopard which specializes in tearing people limb from limb.

Charlie Chan is an agent of the US government working in Washington DC and he is assigned to investigate the murder of the inventor of a highly advanced torpedo. Aiding Chan is his overeager but dull-witted son Tommy and his daughter Iris.