Cold-hearted veteran Cole becomes the personal bodyguard of Julian, the heir of an old-money family. After a kidnapping, he discovers that the returned Julian is not human but a deep-sea monster named Elio. Elio wears Julian's skin, devours part of his memories, and develops a morbid attachment to Cole. Cole cannot expose it, nor can he escape it. He stays close and protects this monster, slowly drowning in a sea of fear, desire, duty, and love.