Marina lives in Merlington, a fish-obsessed seaside town. Unfortunately, she doesn't care for fish; she loves telling stories. Marina finds her best story yet when she explores the ruined, haunted pier: a boy called William with a head of tentacles and crab claws for hands. He has lived on the pier all his life, cared for by a fisherman who has since disappeared and who warned him always to remain hidden. Together, the pair resolve to unravel the mystery of his past - but danger lurks among the fishmongers...