On a stormy night, everything goes wrong. A ship wrecks against the rocks, and the lighthouse keeper and his daughter, Lampie, are separated. Lampie is sent away to work as a maid in the admiral’s black house, a place rumored to harbour a monster. Refusing to give up on finding her father, Lampie teams up with her friend, a boy who is also a fish, and does everything in her power to find her Dad.