In a bizarre and surreal realm, a house in Venice, California conceals a hidden portal within its basement, leading to the Sixth Dimension—a fantastical, absurd underworld ruled by the tyrannical Queen Doris and her lascivious consort, King Fausto. The Hercules family discovers this entrance, and Frenchy Hercules, drawn by curiosity, inadvertently stumbles into this strange world. As she explores the zany and often dangerous landscape of the Sixth Dimension, Frenchy encounters a variety of eccentric characters and faces numerous challenges, including the manipulative Queen and her devious plans.

Frenchy's family, now aware of her predicament, embarks on a rescue mission into the unpredictable and madcap Sixth Dimension. Each member of the Hercules family faces their own set of whimsical trials and encounters an assortment of peculiar inhabitants who hinder or aid their quest. Their journey is a whirlwind of musical numbers, eccentric costumes, and surreal sets, creating a kaleidoscopic cinematic experience. As they navigate this otherworldly domain, the family's bond and resourcefulness are tested, leading to an ever-escalating series of fantastical events.