The Phantom Tollbooth
While Milo's brave enough to start his journey alone, he's lucky in that he spends most of it with his new, faithful companion Tock. Tock shows up at one of the first events Milo has in the Lands Beyond, and helps him break free of the Lethargarians and their Doldrums. Then, Tock stays by Milo's side faithfully as Milo explores as far as Dictionopolis and then decides to go on his quest. It seems like Tock would stay by Milo's side forever…as long as Milo stays in the Lands. When Milo has to go back home, Tock can't go with him. He has to stay in his own native place.