After destroying the Demon King's lair, Anastasia Sokolov believes her and her cousin's lives are finally safe. Unfortunately, when a King who practices necromancy is determined, more than mermaids are needed to destroy the demon clan. Anastasia's cousin Jo, has warned her to keep away from their new accountant, dashing and handsome, Arkin. Arkin is infatuated with Anastasia, but it isn't until he asks for her help she comes to realize why. In a desperate attempt to become immortal, Arkin had joined the demonic, Destria Organization. But when a deadly assassin learns of his plans to escape, Arkin turns to the only one who can save him. With the King's ability to change bodies each time he dies, there is no way of telling friends from enemies apart. As the assassin threatens to destroy any hope of peace, Anastasia learns just how inhuman her friends and boyfriend really are. A dagger from the other world, creatures who are neither human nor animal, and a web comic detailing future events are all Anastasia can rely on. And when the assassin's interests turn to her beloved cousin, Mason, where is the line between who should live and who should die?