Max is a lonely child who creates an imaginary dream world called Planet Drool. He also creates two characters: Sharkboy, bred by sharks, and Lavagirl, who can produce fire and lava. The next day, two tornadoes form outside the school. Sharkboy and Lavagirl emerge from the tornadoes and cause Max to accompany them on Planet Drool, which he discovers is getting worse because of Mr. Electric, a powerful tyrant. So Max, together with Lavagirl, Sharkboy and Marissa, fight against Mr. Electric, to save the Planet of dreams ..