A busload of travelers and their disgraced priest tour guide, on the hunt for Aztec ruins, decide to stop in a Mexican village on the eve of the Day of the Dead. Unbeknownst to them, a local doctor plans to begin a diabolical ritual intended to bring about Hell on Earth.

Frank Bigelow is about to die, and he knows it. The accountant has been poisoned and has only 24 hours before the lethal concoction kills him. Determined to find out who his murderer is, Frank, with the help of his assistant and girlfriend, Paula, begins to trace back over his last steps. As he frantically tries to unravel the mystery behind his own impending demise, his sleuthing leads him to a group of crooked businessmen and another murder.

Told in flash back, the stooges tell their son how he came to have three fathers. The stooges, owners of a pawn shop, owed money to the gashouse protection society, a bunch of loan sharks. To complicate matters, a lady leaves a baby in the shop as part of a plan to sell a phony diamond and the stooges wind up caring for the kid. The stooges manage to defeat the crooks and when they finish telling the story, the kid goes off to find his real mother.