One day SpongeBob had a dream of becoming manager of the crusty crabs to make the restaurant a bigger and better place to eat. Meanwhile, Plankon, Krabs’ business rival, and enactes a plot to steal the Krabby Patty secret formula burger with the dreaded “Plan Z”; Plankton steals king Neptune’s beloved crown (exposing Neptune’s baldness, which blinds anyone who looks at it with a very bright light), sends it to Shell City, a hazardous location known to all marine life. Plankton then frames Mr. Krabs for the crime. Incensed, Neptune crashes into the Krusty Krab 2 and assaults Mr. Krabs SpongeBob later arrives and bad-mouths Krabs, but also promises Neptune that he will retrieve the crown from Shell City, but Neptune doubts that SpongeBob is capable of that. He orders SpongeBob to be back with the crown back in exactly ten days, The hero is charged with a quest to find King Neptunes crown but thanks to Patrick, who seems to want to help his friend, the time is argued down to six days. So he will not run away, Neptune freezes Krabs with his trident and says that Krabs will fry if SpongeBob does not complete his task. SpongeBob and Patrick then head off for Shell City is a car shaped like a Krabby Patty. With his rival frozen solid, Plankton steals the Krabby Patty formula with ease. He also sends a hitman named Dennis to pursue SpongeBob and Patrick.
Squidward uncovers the truth about Plankton stealing Neptune’s crown and attempts to alert the authorities, but Plankton uses mind-controlling buckets, disguised as souvenirs, to control the residents of Bikini Bottom, including Squidward, and renames the city Planktopolis.On the way to Shell City, SpongeBob and Patrick encounter many death-defying obstacles, but their overt goofiness saves them each time. Finally, they approach a trench filled with carnivorous creatures. Before the two admit defeat, Neptune’s daughter, Mindy, appears to give them encouragement by falsely claiming they are men, not kids. Singing a song, SpongeBob and Patrick dance their way across the trench with ease, only to meet a mean biker dud Dennis on the other side. Before Dennis steps on them with his giant boot, he is stomped on by a human boot and token away. The human, revealed to be the Cyclops Mindy warned them about, grabs SpongeBob and Patrick and heads off for his store by the beach, which is in fact “Shell City” itself on land. Then the Cyclops places them under a lamp to dry up fry and die. When they arrive, SpongeBob and Patrick find the crown, but encounter a lethal drying-out process which nearly kills them. However, their tears short-circuit the heat lamp, which releases smoke and activates the emergency sprinkler system, reviving them, as well as the other dried-out sea creatures being sold as souvenirs. While the sea creatures attack the Cyclops, including a lobster who sprayed Elmer glue onto him, SpongeBob and Patrick take the crown out to the beach. After accidentally losing the bag of winds Mindy gave to return to Bikini Bottom, David Hasselhoff offers the two a ride, which they gladly accept. On the way, Dennis catches up to them, but is struck by a catamaran back into the sea. Back at the Krusty Krab 2, Neptune arrives to execute Krabs, while Plankton eagerly watches. In the nick of time, SpongeBob and Patrick return with the crown, save Krabs, and then confront Plankton. In turn, Plankton drops a mind bucket on Neptune. Just as Plankton thinks he is triumphant and has won, SpongeBob, cherishing the fact he is just a kid and that he accomplished a lot in the past six days, uses his imagination to play the Goofy Goober theme in the form of a rock song (a parody of I Wanna Rock” by Twisted Sister), using his Guitar to free Plankton’s slaves. Realizing defeat once again, Plankton tries to escape, but is trampled by Bikini Bottom’s citizens. Plankton is arrested and incarcerated. King Neptune thanks Mindy for her bravery and unfreezes Krabs, who graciously gives the title of general manager of the Krusty Krab 2 to SpongeBob. In the end credits, SpongeBob is seen doing jobs and chores for Mr. Krabs with an oversized Krusty Krab employee hat.