When SpongeBob and Patrick find Squidward is recovering from a bicycling accident, SpongeBob and Patrick decide to take Squidward jellyfishing with them so that he can have his "best day ever." Good intentions notwithstanding, SpongeBob and Patrick thrust poor Squidward into the far more hazardous rigors of their favorite pastime. SpongeBob falls victim to a scheme by the evil Plankton, Mr. Krabs' minuscule arch-rival with the Napoleon complex. Plankton hides out in SpongeBob's head and takes control of his brain. SpongeBob finds he must fight his own body to prevent himself from handing over the secret Krabby Patty recipe to Plankton.