Natsuki is unlike other girls. She has a magic wand and a transformation mirror. She could be a witch or an alien from another planet. Along with her cousin, Yuu, Natsuki spends the summer in the wild mountains of Nagano, dreaming of other worlds. When a terrible chain of events threatens to separate the two children forever, they make a promise: to survive, no matter what. Now Natsuki is grown up. She leads a quiet life with her husband and tries to survive by pretending to be normal. But Natsuki's family demands grow, her friends wonder why she's not pregnant yet, and dark shadows from her past haunt her. Fleeing the suburbs for the mountains of her childhood, Natsuki prepares to reunite with Yuu. Will he remember their promise? And will he help her keep it?