After a tattletale from Terrence, Mac's mother finds out that Mac has been visiting Foster's Home behind her back. She forbids him from visiting Foster's anymore. Mac is now conflicted on whether to grow up and leave a normal life or keep playing with the imaginary friends who matter to him. But because he's a kid and he thinks his family's unfair to him, he chooses the latter. Now Mac, Bloo, and the gang head off on this big adventure in the expanded world of imaginary friends. Terrance follows them from behind, hoping to catch Mac and send him back to Mom's and make his life more miserable.
