What is the main idea in the story collection, Mainly in Moonlight?

Gray believed that people need something joyously unexpected in their lives as an escape from day-to-day problems and as inspiration to make life's challenges easier to overcome. Mainly in Moonlight is a collection of short stories about the impossible. They tell about sorcerers both powerful and inept, princes caught in spells and set free from spells, dazzling castles, and fearsome quests.