Synopsis

Over the gentle strains of Hawaii music, the FRENCH NARRATOR welcomes the audience to Bikini Bottom, home to many SEA CREATURES—and, of course, to SPONGEBOB  SQUAREPANTS (Bikini Bottom Day). SpongeBob greets his pet snail, GARY, and gets ready for his day at work. Sponge Bob's best friend PATRICK, his cranky neighbor SQUIDWARD, and squirrel scientist SANDY CHEEKS all say hello—but the revelry is interrupted by a small earthquake.

The French Narrator describes the two restaurants in Bikini Bottom: The Krusty Krab, run by MR. KRABS, and The Chum Bucket, run by SHELDON J. PLANKTON and his wife, KAREN. SpongeBob arrives to work at The Krusty Krab just as Mr. Krabs is promising his daughter, a whale named PEARL, that she'll be manager someday.

Another rumble from the ground occurs, and news anchor PERCH PERKINS reports that smoke has been sighted at top of the long-slumbering volcano Mount Humongous. The MAYOR of Bikini Bottom informs everyone that if the volcano erupts, the town will be destroyed. Though SpongeBob prefers to look on the bright side, Sandy informs him that the volcano is due to erupt the very next day. Patrick is panicked, but SpongeBob reminds him that they’re best friends (BFF).

In the town square, the citizens of Bikini Bottom are panicking. Patrick suggests that, if they close their eyes, maybe nothing will happen, which gets the attention of the SARDINES. Sandy tries to explain how to save the town scientifically as Plankton and Karen hatch a plot: they will hypnotize the whole town into liking chum burgers by throwing doubt at sandy (When the Going Gets Tough). Plankton suggests that they need a giant escape pod to take them all to a new town named Chumville, and to pay for the pod, they'll hold a benefit concert. Squidward is thrilled at the idea of performing in a concert (Look Out World (‘Cause Here I Come) #1) but the town decides to invite the ELECTRIC SKATES, a rock band, instead. The Mayor makes Squidward the Official Concert Organizer. Though it seems that everyone's minds may have been made up, SpongeBob still hopes to save the town
((Just A) Simple Sponge).

SpongeBob informs Mr. Krabs that he is putting together a team to save the town, but Mr. Krabs’ only priority is escaping with his money—even over his daughter, Pearl (Daddy Knows Best). SpongeBob heads to Patrick's rock to get his help. Patrick has become the Sardines’ doomsday leader but goes with SpongeBob to get Sandy from the Jellyfish Fields. Because of Plankton, Sandy is taking the blame for the Mount Humongous disaster with the Townfish, but SpongeBob convinces her to help (Hero Is My Middle Name –Parts 1 & 2).

In the Town Square, Squidward is organizing the concert and looking forward to performing at the Bikini Bottom Bandshell (Look Out World (‘Cause Here I Come) #2).  The Electric Skates hand him a list of items to gather for them before the concert written on a roll of toilet paper, promising to let him perform if he can get everything on the list. Meanwhile, Plankton informs SpongeBob and his team that no one has ever made it to the top of Mount Humongous alive—ever. Though SpongeBob and Sandy are undeterred, the Sardines convinced Patrick to stay behind (Super Sea Star Savior), upsetting SpongeBob.

As tensions rise in the town, Plankton and Karen reveal their Avalanche Maker 3000, which is their plan to make sure that SpongeBob doesn't succeed in stopping the eruption. Patrick realizes that he made a mistake by abandoning SpongeBob.

Meanwhile, Squidward has gathered all the items on the Electric Skates’ list except one. The band performs and invites Pearl to be their backup singer (Bikini Bottom Boogie). As Squidward prepares for his performance, the Electric Skates stop him because he missed an item on their list: sea horse radishes. They call Squidward a loser and exit, but Squidward isn't done (I'm Not A Loser).

As everyone gathers to leave, the town discovers that even with the benefit, they do not have enough money to purchase the escape pod. Pearl offers Mr. Krabs’ money to pay for it, and the Mayor seizes his assets, but it's still not enough.

Meanwhile, SpongeBob and Sandy are preparing to climb Mount Humongous. When SpongeBob has a moment of crisis, Sandy convinces him to keep going (Chop To The Top). Though Sandy and SpongeBob make progress, Karen and Plankton fire the Avalanche Maker 3000. Just when SpongeBob starts to slip, Patrick shows up with the jetpack to save them! SpongeBob is the only one who can squeeze through the tight quarters with the Eruptor Interrupter, and Patrick reminds him that he has everything it takes to save the day: management skills (Simple Sponge–Reprise). SpongeBob tosses the Eruptor Interrupter and they parachute down the mountain.

Back in Bikini Bottom, SpongeBob rallies the town as everyone waits to see if the Eruptor Interrupter has worked (Best Day Ever). The Townfish countdown together… and Mount Humongous doesn't erupt! Everyone comes together to celebrate the victory (Finale: Bikini Bottom Day).