The boy Arthur (10) wakes up sad in the morning and is accompanied outside by his mother on his way to school. Shortly before that, he meets the moon child in the playground. She asks him to show her the world and Arthur walks with her through the city, an industrial estate, a forest, to a large meadow where their journey ends. Along the way, Arthur has explained the human world to her, which she knew nothing about, and in turn asked her existential questions about her, life and death. Shortly before the moon child has to leave again, we learn what has happened to Arthur and he is left alone in the meadow before the day ends.