Amidst the East Sea's cyclopean depths, which conceal horrors beyond human reckoning, there dwells a solitary merman named Zi Yu. He lives perpetually on the treacherous periphery of The Safe Shallow-the fragile nexus where the world of mortals brushes against the shadowy kingdom of the mutated fish-kind. When unnatural storms descend, accompanied by an absolute, terrifying silence emanating from The Abyss itself, Zi Yu unwittingly rescues an enigmatic creature bearing wounds of unnatural origin, forever binding his fate to the unfathomable darkness below.