Mystery writer Cornelia Van Gorder has rented a country house called "The Oaks", which not long ago was the scene of some murders committed by a strange and violent criminal known as "The Bat". Meanwhile, the house's owner, bank president John Fleming, has recently embezzled one million dollars in securities and has hidden the proceeds in the house, but is killed before he can retrieve it.

Elsa Carlyle is impulsive and a gambler. Though loved by her husband Jeff, she's spoiled and selfish, concerned with social standing. Meanwhile, Jeff wants to stop spending while he completes business deals that could make them rich. One night, on a hunch, she bets and loses big at a casino, and then she doubles her problems with more impulsive decisions. Hardy Livingstone, a wealthy Casanova just back from the Orient, makes a play for her. Elsa dallies with Hardy, but soon, his insistence and her dire financial affairs seem destined to lead to adultery. Who's the cheat?