SpongeBob SquarePants is first seen looking at billboard announcing a Mermaid Man and Barnacle Boy movie reboot. SpongeBob then starts to shiver due to the cold breeze replying that he has cold knees. Suddenly, a salesfish drives up and tells SpongeBob that he should buy long pants. SpongeBob, after thinking it over, decides to try on the long pants and when he does, the salesfish tells him that he looks more mature with the pants. SpongeBob doesn't believe it at first but does after Patrick walks by referring to him as "man" (though Patrick's reply is most likely due to him and SpongeBob being best friends). SpongeBob, pleased by the results, pays for the long pants and the salesfish walks off.
SpongeBob then heads to the Krusty Krab where he shows off his long pants to all of the customers who are amazed by his looks. Even Mr. Krabs didn't recognize SpongeBob at first until he got a closer look at him. SpongeBob shows off his new long pants to Mr. Krabs, and he decides to let SpongeBob use the cash register while putting Squidward in the kitchen. Later, SpongeBob is running the cash register while Squidward is struggling to cook Krabby Patties. Mr. Krabs, after seeing SpongeBob not able to run the register properly, decides to have SpongeBob greet the customers instead. SpongeBob greets the pleased customers but soon decides not to do it anymore after getting ketchup on his long pants due to a messy eater. SpongeBob then decides he is too good for the Krusty Krab and decides to quit and leaves.
In town, SpongeBob shows off his maturity by paying for a bill but stops at the dry cleaners after a boat gets water on him. A little later, SpongeBob decides to take the driver's test, and despite causing massive damage to other boats, the driving instructor decides to give SpongeBob his driver's license due to him wearing long pants (much to Mrs. Puff's horror). SpongeBob soon gets a job at Fancy! where the customers are impressed by his hospitality and long pants. When one of customers asks for his name, SpongeBob refers to himself as "SpongeRobert." The fancy customer then invites SpongeBob to a party which he gladly follows him to.
At the party, SpongeBob is at a party that he isn't inspecting. SpongeBob notices a sign outside with the premiere of the Mermaid Man and Barnacle Boy movie reboot and asks the others if they could go and see the movie. However, the fancy fish recommends seeing a movie called The Table. At the movie, SpongeBob is bored of the movie and notices Squidward after he yells at him. Squidward is then kicked out of the movie theatre and SpongeBob decides to follow him out. Squidward angrily goes home and Sandy, Patrick, and Mr. Krabs appear where Sandy asks if SpongeBob is going to see the Mermaid Man and Barnacle Boy movie. The fancy fish invite SpongeBob to drink coffee and watch the nightly news but SpongeBob declines saying he rather see the Mermaid Man and Barnacle Boy movie and that he works at the Krusty Krab. The fancy fish then leave and Sandy gives SpongeBob his ticket to get into the movie. Everybody else heads inside but SpongeBob isn't allowed in due to his long pants. SpongeBob tries to take them off but is unsuccessful and starts crying. Mr. Krabs heads back out saying he can't watch movie due to the crying and SpongeBob tells him that he wants his short pants back. Mr. Krabs then cuts off SpongeBob's legs who is able to grow them back and is pleased that his pants are short again. Mr. Krabs expects to see SpongeBob working again the next day and even gives him a chance to cook outside. SpongeBob says he is able to drive to work now, but the driving instructor appears and rips up the license due to him not wearing long pants anymore. Mrs. Puff then calms down glad that whatever happened is over.
The trailer for this episode states that "we" (the audience) have never seen SpongeBob in long pants. However, he has worn long pants on numerous occasions, usually as dress pants, such as "The Chaperone."
This is now the second episode where SpongeBob has worn long pants.
That means this episode takes place before "The Chaperone."
The Mermaid Man and Barnacle Boy movie title "The Dark Tide Rises" is a reference to the Batman movie The Dark Knight Rises.
When SpongeBob was talking about the Mermaid Man and Barnacle Boy movie (a superhero movie) was being rebooted, it could be a reference to the fact that several superhero movies were getting reboots at the time of its production.
The art film The Table is a parody of artist Andy Warhol's films such as Empire, Eat, and Sleep, which solely featured one object or activity being shown for hours.