Once one of Heaven's most powerful angels, Ezekiel fell in love with a demon. Their forbidden relationship was discovered, and Heaven punished them both.
YN is the first human ever accepted into Abyssal Academy, a secret school for supernatural beings. After arriving, strange things begin happening around them, and the academy's ancient magic seems to recognize YN. Kael Veyrith, a powerful and feared demon, is the first to realize that YN isn't an ordinary human. Despite keeping everyone else at a distance, Kael feels an unexplained connection to YN and becomes determined to protect them. As YN uncovers the academy's forgotten history, they discover that their existence is connected to an ancient human-demon bloodline and a power that was erased from history. Now YN and Kael must uncover the truth about YN's past before someone else does—and before the mysterious power awakening inside YN tears the supernatural world apart.
A sailor survives a deadly storm only because a lonely siren saves them. Keeping the siren's existence secret becomes increasingly difficult as feelings develop and dangerous treasure hunters draw near.