SpongeBob wakes up one morning and finds out that Gary is missing, and discovers that he is the only one left in Bikini Bottom. At first, SpongeBob finds this hard to take. In panic, he runs around town in a desperate attempt to find someone, only to find no one.
When the others do not return, SpongeBob then decides to live out everyone's lives for them. He makes a bubble version of himself in his front yard, then runs to the top floor of Squidward's house, pretending to be Squidward yelling at SpongeBob for making too much noise. SpongeBob then runs to the Krusty Krab, imitating Squidward and Mr. Krabs. He imitates Sandy at the Treedome and Patrick in his house before running to the boating school and pretending to be Mrs. Puff.
In the classroom, he realizes that living out everyone's lives will not work, and he breaks down crying on Mrs. Puff's desk. SpongeBob's mood quickly changes when he discovers a stack of blank driver's licenses. He takes a picture of himself, and prints out his own license. He then takes off with the student test boat, naming it "Boaty," and joyriding throughout the city.
SpongeBob and Boaty become inseparable best friends. SpongeBob sleeps with the boat, and parks it inside both his house and the Krusty Krab. SpongeBob is going insane without people to talk to, and Boaty realizes this. In his closet, SpongeBob has erected a statue of Patrick out of raw Krabby Patty meat, which he carries out a conversation with. The "Patty-Patrick" warns him that he cannot talk because Boaty is listening. He goes crazy from the sight of any motor vehicle, and when a bus comes, he grabs a fire ax from the cinema to chop at the bus that approaches him.
To his surprise, everyone in Bikini Bottom comes out of it. Mr. Krabs tells SpongeBob that everyone's mysterious disappearance was really a holiday to celebrate being away from SpongeBob for a day (according to SpongeBob, they were gone for weeks) called National No SpongeBob Day. Before venturing off, a giant effigy of SpongeBob is erected, and then burned. Everyone then dances on the ashes to celebrate. SpongeBob is deeply saddened by this but Mr. Krabs tells him that the holiday is an honor. Patrick recommends a "No Patrick Day." After Patrick says this, everyone celebrates National No Patrick Day and boards the bus except for Patrick, obviously forgetting what he just said.
The characters that Spongebob is seen impersonating include:
Old Man Jenkins
On SpongeBob's driver's license, it says that his hair color is yellow and that he only weighs one ounce.
Oddly, SpongeBob's scallop does appear at the beginning of the episode, but is completely ignored as a living creature. The pet probably could not go with the rest of the Bikini Bottomites because it is trapped in a birdcage.
SpongeBob was able to walk right into the Krusty Krab in the morning, without Mr. Krabs unlocking the door. However, in "The Lost Mattress," Mr. Krabs had to unlock the door so they could go inside. Perhaps he left it unlocked for SpongeBob to get in..
This is the second time SpongeBob is seen impersonating Mr. Krabs. The first time was in "Shell of a Man."
At the end of the episode, Patrick is seen holding three balloons that depict his three main colors: pink for his skin, green for his shorts, and purple for the flowers on his shorts.
It may also be a parody of the Twilight Zone episode "Where is Everybody?," where a man finds himself the only man in town, and is nearly driven to the point of insanity.
Mr. Krabs recalling about burning down an effigy of SpongeBob is a reference to The Burning Man.
The red bus has a pipe on top resembling the quail crown.
SpongeBob and his boat that moves on its own could be a parody of the novel and its adaptation, Christine, about a car possessed by supernatural forces.
When SpongeBob was trying to "keep Sandy's memory alive," he was not wearing his water helmet in Sandy's Treedome, and was able to breathe. He also did not take her shape as of everyone else.
When everybody gets back on the bus, Gary, Sandy and most of the other Bikini Bottomites are not seen.
On the shot where SpongeBob is Squidward and the empty Kelpo cereal box is SpongeBob, three out of four limbs are toilet plungers.
When SpongeBob goes to his boating school, he is wearing a dress similar to Mrs. Puff's dress. When he starts to get upset and sees the blank driver's licenses, he wears his normal clothes again.
When SpongeBob puts Boaty on the patties to make Krabby Patties and floors it, only the wheel on the Krabby Patties moves, but the wheel on the other side does not move at all.
At the end, SpongeBob becomes terrified of all vehicles, as Boaty was continually watching him, and he attacks the front of a bus with an axe. When everyone leaves for No Patrick Day, however, the axe is gone.
When SpongeBob got his boat, the boat's seat is red. But when SpongeBob crashes into his house, wanting to sleep, the boat's seat turns purple.
When SpongeBob was driving Boaty around, he crashed into many things without giving Boaty a dent.
When the Bikini Bottomites come out of the bus, some appear out of nowhere.
SpongeBob's mouth did not move when he called for Patrick.
In shot of the outside of SpongeBob's house and some wind blowing lots of leaves, lots of things such as Squidward and Patrick's houses are missing.
The lights in Squidward's house appeared to be on when SpongeBob went in to ask if he has seen Gary, but from outside, they are not on.
When SpongeBob went to sleep, Boaty was halfway in his pineapple, but later, it was in the bed with SpongeBob. However, it is possible that SpongeBob woke up once and placed it there.
When SpongeBob is talking to the Krabby Patty Patrick, Krabby Patty Patrick gets significantly smaller when the scene shows Boaty in the background.
SpongeBob says that it had been weeks sine the Bikini Bottomites were gone, but it had only been six days.