After receiving a long-awaited heart transplant, a professional gamer girl begins to develop strange abilities and is soon launched into a mysterious world filled with fantastical and deadly creatures and ruled over by an extremely seductive man.

Baden, having spent centuries in purgatory, is now bound to the king of the underworld and quickly devolving into a heartless assassin. When his mission goes awry, he finds himself saddled with dog trainer Katarina Joelle, someone else's bride, as his hostage. Katarina is plunged into a war between two evils, with a dangerous protector--but is he more dangerous to the monsters he hunts, or to her heart?