Karada's wish to grow up and no longer be a burden, and Shouko's desire for a fresh start, take an unexpected twist. The wishing stone grants both their wishes (Karada "grows up", in body at least, and Shouko's forced into a new life, in a child's body), and so they're forced to re-connect with themselves and each other. True to the symbolism of them "switching places", you could say that, within Karada and Shouko, they'll find the "missing pieces" of each other. In the midst of all this is Hiro, Shouko's ex-boyfriend and Karada's non-blood-related older brother; Hiro abandoned his relationship with Shouko to stay by Karada's side after the death of her parents (and she doesn't know they're not blood-relatives). The show is carefully weaving it's way through the characters and their pasts in an attempt to provide reconciliation and closure. It's a deliberately-paced slice-of-life drama focused entirely on characters and human relationships, probably most akin to something like Hanbun no Tsuki ga Noboru Sora, among others (that's just the first example that comes to mind, since it has the same music composer).