Asahi, a little girl with loving parents and a peaceful life, is sucked into the pond in her family's garden and surfaces in a world that looks like ancient Japan. Subaru, a boy from the nearby village, takes her in, but that same night the villagers sink her in the lake as a sacrifice and bride for the water dragon god. The god, who has never cared about human feelings, finds her strange, takes away her voice and promises to give it back once she is old enough to be his wife. Unable to go home, Asahi resolves to survive in this world.