Dreamer Max, ridiculed by his classmates, conjures up his perfect dreamworld...the Planet Drool. But his dream is more powerful than even he suspects, and his favourite dream super-heroes, Sharkboy and Lavagirl, materialise on Earth. They need help from Max. All is not well in Max's dreamworld. An alien intelligence is interfering and darkness threatens his beloved Planet Drool. Is it true, as Sharkboy and Lavagirl say, that only Max, the powerful dreamer, can stop it? Max takes off on a wild and dangerous journey to the fantastic Planet Drool with Sharkboy and Lavagirl. Can they discover the source of the danger? Will they be able to stop it in time?

The siblings Noah and Emma travel with their mother Jo from Seattle to the family cottage in Whidbey Island to spend a couple of days while their workaholic father David Wilder is working. They find a box of toys from the future in the water and bring it home, and Emma finds a stuffed rabbit called Mimzy, and stones and a weird object, but they hide their findings from their parents. Mimzy talks telepathically to Emma and the siblings develop special abilities, increasing their intelligences to the level of genius. Their father becomes very proud when Noah presents a magnificent design in the fair of science and technology, and his teacher Larry White and his mystic wife Naomi Schwartz become interested in the boy when he draws a mandala. When Noah accidentally assembles the objects and activates a powerful generator creating a blackout in the state, the FBI arrests the family trying to disclose the mystery. But Emma unravels the importance to send Mimzy back to the future.