When Mac accidentally imagines another friend, Bloo suffers sibling rivalry with the newly arrived and very odd Cheese.

Wilt runs away in search of his creator after he receives no visitors at the annual picnic, so Bloo and the gang head out to find him and discover some interesting things about Wilt's secret past along the way.

Mac and Bloo fall for Frankie and become wildly jealous of each other and everyone else.

Frankie is tired of working without being thanked. One day, a toy box is discovered at Foster's front door. Frankie is ordered to take it to the attic and leave it alone, but she knows there is an imaginary friend trapped inside, and opens the box to find it. When she looks inside, she falls into a strange imaginary world. There, she gets treated like a princess by a mysterious imaginary friend. After tackling certain bizarre toy box trials and tribulations, Bloo, Mac, Wilt, Eduardo, and Coco discover Frankie's whereabouts and set out to rescue her from this strange world. This is the first and only episode to have a TV-PG rating.

Bloo takes Mac for a secret ride on the Foster's bus.

Wilt runs away in search of his creator after he receives no visitors at the annual picnic, so Bloo and the gang head out to find him and discover some interesting things about Wilt's secret past along the way.

Mac and Bloo meet residents Eduardo, Wilt and Coco, and the home's staff.

Bloo becomes a celebrity as a deodorant mascot, but fame taints his relationship with Mac.

As everyone gets ready to take the annual house photo, Mac and Bloo notice another picture that was taken years ago.

An evil imaginary friend sets a sinister plot in motion against Bloo, and Mac and the home's residents must save him.

A new Imaginary Friend named Berry has her eyes on Bloo, and Mac stands between them.

Mac and Bloo have a fun day by themselves in the mansion.

A prank gone wrong has Bloo trying to outrun an army of zombies.

Mac tries to thwart Bloo's plans for a party.

Frankie faces a tough campaign against Mr. Herriman as they both compete to be president of Foster's.

Bloo is teased by a child who lives across the street.

Mac is surprised when Bloo and the rest of the gang show up at his place for a slumber party.

Everyone gets locked out of the home, and only Cheese knows the code to get back in.

Bloo decides to open the one door at the retirement home for imaginary friends that is never, ever to be opened, and the house becomes infested with something bad.

Mac and Bloo get embarrassing footage of Mr. Herriman while conducting interviews for a Web site.

Eduardo breaks the "no dogs in the house" rule.

Mac gets the gang to join a bowling team, but ends up getting booted off.

A Seeing Eye Friend loses his blind kid, and the gang helps find him. Then Boo becomes popular among Mac's classmates, who imagine their own versions of Boo.

A camping trip becomes a problem when Bloo eats all the food.

Mac and Bloo collaborate on a movie, which turns into a hit. Later, they must make an even better sequel for a film contest.