The Phantom Tollbooth
The Humbug becomes Milo's guide in spite of himself. He knows exactly how to get to the Castle in the Air and shows this off when he tells King Azaz what Milo should do to accomplish the rescue. But, of course, he has no thought of going himself. Once he's forced along, though, the Humbug pulls himself together and makes the best of it. He also proves himself a pretty good guide: the small group follows the path he set out and actually ends up at the Castle in the Air. Mission: accomplished.