Nia, a 22-year-old biological prodigy, accidentally plunged into the deep sea, where she was forcibly "marked" by Sane—a breathtakingly beautiful yet utterly ruthless Merfolk Alpha. Determined to uncover the truth behind her father's murder, Nia escaped the depths and infiltrated the sinister Ocean Research Institute (ORID), even going so far as to feign a romance with Marcus, the hypocritical killer responsible for her father's death.
Three years later, just as Nia was on the verge of uncovering the truth, Sane made a powerful comeback, transforming into a suit-clad tycoon. The cold-blooded Merfolk tyrant unleashed a frenzy of jealous possessiveness, confining her within a "locked-room" captivity. Yet, standing before a cruel experimental tank, Nia made a terrifying discovery: she was not human at all, but a rare Merfolk-human hybrid Omega.
When the villain exposed her identity and attempted to drown her, her dormant bloodline fully awakened. Witnessing his mate’s torment, Sane transformed into a deep-sea demon of vengeance; he slaughtered everyone in the lab and swept her back into the abyss, where he claimed her—body and soul—in a cross-species union amidst the weightless depths.
As human depth charges detonated on the ocean floor, Sane rallied a global Merfolk army, intent on unleashing a cataclysmic tsunami to annihilate the land. Caught between humanity and the Merfolk, how would Nia—now a hybrid queen—use her power to tame this bloodthirsty beast who had gone mad for h
