A young woman begins to suspect that her brother's young fiancée, an attractive Englishwoman, is actually a serial killer who kills men on the eve of their weddings.

The monstrous Penguin, who dwells in the sewers beneath Gotham, joins up with corrupt mayoral candidate Max Shreck to topple the Batman once and for all. But when Shreck's timid assistant Selina Kyle finds out, and Shreck tries to kill her, she's transformed into the sexy Catwoman. She teams up with the Penguin and Shreck to destroy Batman, but sparks fly unexpectedly when she confronts the caped crusader.