A group of delinquents on their way to summer camp get stuck in a haunted house.

A seemingly charitable soup kitchen operator (who moonlights as a criminology professor) uses his Bowery mission as a front for his criminal gang. Police attempt to close in on the gang as they commit a series of robberies, murders and bizarre experiments on corpses.

Dr. Paul Carruthers is frustrated because he thinks his employers, Mary Heath and Henry Morton, have cheated him out of the company's profits. He decides to get revenge by altering bats to grow twice their normal size and training them to attack when they smell a perfume of his own making. He mixes the perfume into a lotion, which he offers as a gift to Mary and Henry. When they turn up dead, a newspaper reporter decides to investigate.