Milo is bored and has nothing to do but, he gets a package and it contains a tollbooth ad a car. It has a map of some places and Milo decides he wants to go to Dictionopolis.
Milo stops thinking on his way there and ends up in the Doldrums. A watchdog named Tock helps Milo get out of the Doldrums and get to Dictionopolis.
Milo meets King Azaz and he gives Milo a box of letters for his journey to save two princesses, Rhyme and Reason. A bug named the Humbug joins Milo and Tock on their journey.
Milo, Tock and the Humbug find the Mathmagician and he gives Milo a magic staff that looks like a pencil. He wishes them luck as they go to save Rhyme and Reason.
They get to the Castle in the Air where Rhyme and Reason are being trapped. They fight off demons and Milo uses the box of letters and the magic staff to save Rhyme and Reason. When they get back to Dictionopolis the Mathmagician and Azaz thank him and tell them that their journey was impossible but because they didn't know they were able to do it anyway.