Plankton steals King Neptune's crown and frames Mr. Krabs. Without something to cover his receding hairline, Neptune goes after Krabs. Spongebob manages to strike a deal with the god of the sea: he and Patrick will embark on a perilous journey to the inconveniently-far-away Shell City to recover the crown (however it suddenly ended up there) if Neptune spares Mr. Krabs's life. On their journey, they'll encounter a buncha creepy monsters in a monster filled trench, fishy thugs from the Thug Tug who make even the toughest fish from the Salty Spitoon cry, and Plankton's ruthless hit man Dennis, who's impeding the progress of our heroes every chance he gets. With the duo out of the picture, Plankton initiates "Plan Z", his ultimate plan to steal the secret Krabby Patty formula and ultimately rule the world.