故事發生在一個被稱為「Seawaren」的小鎮。兩百年前，「廢墟」毒害了大地，迫使人類退居海岸一隅。而大海，早已被這股毒素改變，成為了「海中怪獸」的領地。而書中的主角 桑妮（Sunny） 從小被教導三個真理：「海怪是危險的、海怪是暴力的、海怪就是怪物。」然而，一次偶然的相遇，桑妮救下了受傷的海怪 阿墨（Mo）。她驚訝地發現，阿墨不僅擁有高度智慧，性格更是溫柔，牠跨越海洋僅僅是為了尋找失散的兄弟。當桑妮冒險保守這個祕密時，飢荒卻襲擊了小鎮。在生存與偏見的夾縫中，桑妮逐漸意識到：真正的怪物，或許並不生活在海裡，而是隱藏在人心深處的恐懼與祕密中。Sunny waited until her mother was asleep before she went back for the monster . . .All her life, Sunny has known three things about the creatures that prowl the seas off her tiny coastal town. They are dangerous. They are violent. They are monsters.But when a chance encounter leads to an unexpected connection, Sunny discovers just how wrong she has been. The monster she meets – Mo – is intelligent, gentle, and searching for his lost brother.Sunny desperately wants to help, and to keep her new friend a secret. But other people are keeping secrets too. And as hunger grips the town, new truths will emerge about the real monsters in Seawaren . . .
