Mermaid Man and Barnacle Boy decide to have lunch at the Krusty Krab. Learning this, Spongebob becomes overexcited and runs for an autograph, prompting the heroes to flee in fear and in the process, Mermaid Man drops his utility belt, which includes many features including a shrinking button, which Spongebob inadvertantly uses to shrink everyone in Bikini Bottom./Spongebob is in the process of failing his driving exam (yet again), and while they plunge off an unfinished bridge, Mrs. Puff imagines many outcomes of the event, one of which is going to jail.

There's trouble brewing in Bikini Bottom. Someone has stolen King Neptune's crown, and it looks like Mr. Krab, SpongeBob's boss, is the culprit. Though he's just been passed over for the promotion of his dreams, SpongeBob stands by his boss, and along with his best pal Patrick, sets out on a treacherous mission to Shell City to reclaim the crown and save Mr. Krab's life.

海绵宝宝第二部本动画的主角，是一块居住在海洋深处的黄色海绵(住所是一个大菠萝(即凤梨)中)，他是一个可爱、慷慨大方、友好、可信赖的朋友。他露出龅牙的笑容，非常富有表现力的脸和身体，以及他纯真美好的天性使他非常可爱。