Mad Monster Party?.Baron Boris von Frankenstein (voiced by Boris Karloff) achieves his ultimate ambition, the secret of total destruction. Having perfected and tested the formula, he sends out messenger bats to summon all monsters to the Isle of Evil in the Caribbean Sea. The Baron intends to inform them of his discovery and also to reveal his imminent retirement as head of the "Worldwide Organization of Monsters". Besides Frankenstein's Monster (referred to as "Fang") and the Monster's more intelligent mate (voiced by Phyllis Diller) who live in the island castle with Boris, the invites also include Count Dracula, the Mummy, Quasimodo (referred to as "The Hunchback of Notre Dame"), the Werewolf, The Invisible Man, Dr. Jekyll and Mr. Hyde, and the Creature from the Black Lagoon (referred to as the "Creature"). The Baron's beautiful assistant Francesca (voiced by Gale Garnett) enters the lab to confirm that all invitations have been delivered and inquires about one of the addressees named Felix Flanken (voiced by Allen Swift). Frankenstein explains that Flanken is his nephew and successor in the monster business. This displeases Francesca who covets the role for herself. Francesca even asks why there was not an invitation for "It". Boris replies that "It" was not invited since "It" can be a crushing bore, explaining that "It" even crushed the island's wild boars in his bare hands the last time "It" was invited...