Insurance salesman Albert Tuttle arrives at the Cyrus J. Rutherford estate to sell the millionaire some life insurance. Rutherford is already dead and his heirs have gathered at the mansion to hear the reading of the will. Rutherford's will won't be read until he is properly entombed and the heirs are forced to stay on the premises or be denied their inheritance. Tuttle soon finds himself mixed up in shenanigans involving Rutherford's niece, secret passages, a missing body and murder.
When a wealthy man (Atwill) is threatened by a killer known as The Gorilla, he hires the Ritz Brothers to investigate. A real escaped gorilla shows up at the mansion just as the investigators arrive.
During World War 2, a small plane off the south coast of America is low on fuel and blown off course by a storm. Guided by a faint radio signal, they crashland on an island. The passenger, his manservant and the pilot take refuge in a mansion owned by a doctor. The easily-spooked manservant soon becomes convinced the mansion is haunted by zombies and ghosts. Exploring, the 3 find a voodoo ritual in the cellar, where the doctor is trying to acquire war intelligence by transferring personalities into his zombies. But the interruption causes the zombies to turn on their creator.