She was meant to become the supreme ruler of the demon realm, but on the day of her coronation, the person she loved plunged a sword through her heart. Her soul entered the mortal world, where she became the third young lady of the Duke's estate, a useless girl who was constantly bullied. Her former cowardice and weakness were gone, replaced by a cold, proud, and rebellious figure. She declared, "If Heaven abandons me, then Heaven can be defied. If the world casts me aside, then the world shall be destroyed. I will avenge this attack on my heart!" But as layer upon layer of mystery is unraveled, whose fated calamity will it prove to be, and who will become whose obsession...