It was just another ordinary day for Milo when suddenly a tollbooth appears out of nowhere and Milo says, "What else do I have do?"
He decides to go through the tollbooth and finds himself in Dictionopolis where he runs into a few random people and after that he meets the Spelling Bee.
In Dictionopolis, Milo gets invited to the king's feast with his new friends Tock, Humbug, and the Spelling Bee only to find out the two kingdoms have been split because Rhyme and Reason were banished so he wants to save them.
As Milo sets off to his adventure, the king gives him a box of letters. When he gets to Digitopolis, he finds out numbers come from mines and he runs into the math magician who gives him a magic wand before he leaves.
When Milo gets to the castle he runs into all the demons and must runaway to open the castle to save Rhyme and Reason
In the end, everybody comes to fight the demons and they won so then they all wished Milo a goodbye and sent him on his way back home.