Bloo plans to throw a wild party when Madame Foster and Frankie are away, but is afraid that Mac will ruin it by telling Mr. Herriman. Bloo gives Mac sugar to stop him from telling, but Mac becomes a sugar-crazed maniac.
Mac and the imaginary friends join Madame Foster's bowling team to help her beat her rival, Jerkins. Mac ends up getting kicked off the team and learning from a bowling expert, and the rival team promises Bloo a paddle ball if he joins them and helps them win.
When Wilt wants to watch a basketball game, he realizes that he can't say no to anyone's requests; A new imaginary friend named Bendy comes to Foster's and causes problems that everyone else is blamed for. Bloo tries to come up with a plan to prove Bendy is the one behind everything.
When a seeing eye friend named Ivan loses his blind kid, the friends help Ivan find him before something bad happens. After Mac takes Bloo to school for show and tell, the students create hundreds of Bloos. Mac then must determine who the real Bloo is before they go to the ice charades.
Mac and Bloo both develop a crush on Frankie, and try to stop her from having any contact with any guy. Eventually, they follow her on a date while in disguise.
Mac realizes that he accidentally created a new imaginary friend named Cheese. Cheese is allowed to stay at Foster's like Bloo, but Bloo has trouble dealing with his new brother Cheese.
At the arcade, the gang, sans Bloo rack up lots of tickets at all of its games. They win a rubber elephant, which Bloo grows to obsess about having. But when he swipes the elephant from Frankie, while she sleeps, he accidentally wrecks it and must replace it before everyone else finds out.
Bloo pretends to be sick in order to appear on TV with the other friends. A Hollywood agent finds Bloo and turns him into a star by having him appear in deodorant advertisements. Soon, Bloo is not even allowed to see Mac.
Bloo discovers that Mac is a nerd, and tries to make him cool. When Mac is invited somewhere by the coolest kid in school and isn't at Foster's at 3:00, Mr. Herriman tries to get Bloo adopted.
Uncle Pockets, the very first friend to come to Foster's, returns. Bloo becomes jealous when Uncle Pockets gets all the attention, and tries to expose him as a fraud by using the house's newspaper.
A rich man is considering giving money to a charity, and wants to see if Foster's is worthy. Mac and Bloo are told to keep Coco out of the way. But Foster's is only considered for the money when Coco is mistaken as Mr. Herriman's wife. Mr. Herriman then tries to teach Coco how to be sophisticated.
