When the rich Cornelia Van Gorder (Moorehead) travels out to a secluded mansion from the city, she steps directly into the setting of a diabolical scheme. The mystery writer immediately faces fear and upheaval from her servants, who clamor on about a murder that took place in the house the year before. Her trusted assistant, Lizzie (Lane), talks about the possibility of rabid bats and a killer called The Bat.
John Fleming (Stephens) quickly reveals that he's embezzled a million dollars in securities to his physician, Dr. Wells (Price). The securities are hidden in the estate recently rented by Cornelia. Immediately, the two begin to hatch a plot to get a hold of the funds, fake Fleming's death, and escape.
Wells turns the table, killing Fleming and scheming to make off with the money himself. Soon, Police Lt. Andy Anderson (Gordon) is off to find the mysterious man called The Bat, who seems to have resurfaced. Wells works his way into the trust of Cornelia, needling her for information, working in his methods of subliminal fright, and furthering his plans.
The body count grows as the mystery writer seeks to find the answers to the missing money and her mansion. It becomes a race between The Bat's murderous ways and Cornelia's cunning. In the end, the mystery is revealed, becoming the latest in Cornelia's string of successful stories.
The Bat opens with a loud brass-driven number, calling to mind the jazz styles of the late 50's. Similar music drives the action, delivering a heart-racing cacophony at all the key times.
Wilbur uses zooming techniques and lighting with deft skill. He makes the most of the elaborate mansion set and the backdrop of thunderstorms to create an air of suspense. He is especially adept at using shadows to enhance the contrast of the black and white film.
Price is once again on top of his game at what he does best; deliver a devilish performance as the heart of intrigue and murder. Moorehead is sure and steady as the fiercely independent Cornelia. Lane brings a great immigrant flavor to her performance as Lizzie Allen, providing a perfect sounding board for Moorehead. The role of Judy Hollander is played by Darla Hood (Our Gang), and would be her final on-screen performance.