In a world of magic, a girl is born with a mysterious ability, her body rapidly adapts to any situation, leaving no weakness for anyone to exploit. The girl named Remilia wanders the world, her body already in a state of near immortality, searching for someone, anyone to end her suffering. One day, after entering the adventuring guild, she finds a quest that interests her, a Quest that labels her as the Demon Queen...

Hoping this might be her chance to finally die, Remila decides to play up the demon queen role, becoming a wandering calamity. Only for the prophesied hero to be completely unable to kill her. Finally exhausted from everything, Remilia falls into a deep slumber and the hero agrees to seal her for as long as possible, but the seal was released by a girl who wanted to awaken the demon queen so that she could get her revenge. This girl was a kindred spirit, a girl with the same ability as Remilia...