Leo is an earnest marine biology graduate student conducting field research on secluded Merfolk Island when he encounters Opal, a breathtaking and predatory siren. Mistaking the aquatic creature's curious stares for innocence, Leo lightheartedly teaches him human romantic courtship rituals, completely unaware that Opal has pined for him for over a decade.
When suppressed memories of an ancient coastal rescue resurface alongside terrifying siren possessiveness, Leo panics and tries to escape the enchanted waters. Trapped within Opal's underwater sanctuary and carrying an impossible mystical child, Leo must reconcile his fears with the fierce devotion of the siren king who claims him.
