A city in black and white. Crazy, chaotic, full of things. A child finds an abandoned helmet -yellow yellow. It becomes his hat. Everybody is looking at him with suspicion, surprise, caution, but he goes around in the city, proud and careless. As long as an adult, ten times taller than him, takes the yellow yellow helmet back. It belongs to him, so the child loses it forever. But, at home, with just his yellow crayon and his fantasy, the little boy will make a new one. And the story can start again.