Agnès, Juliette and Carmen's neighbour, writes children's storybooks that take place in a fantasy world, The Kingdom of the Winds. The intrepid sisters discover a passageway between their world and this extraordinary universe. Once on the other side, the girls take on the appearance of cats and discover Sirocco, a terrifying character who can control the wind.

The world is a perplexing, peaceful mystery to Amélie until a miraculous encounter with chocolate ignites her wild sense of curiosity. As she develops a deep attachment to her family's housekeeper, Nishio-san, Amélie discovers the wonders of nature as well as the emotional truths hidden beneath the surface of her family's idyllic life as foreigners in post-war Japan.