Marie is reincarnated as the nanny from a seedy fantasy novel. She has to take care of Brielle, a baby who is the villain destined to destroy the world, but all she wants is a normal, peaceful life. Marie meets Brielle's uncle, a cold and ruthless knight who is the king's right-hand man. He neither despises nor worships her, but protects her with his sword and his heart. They will have to face enemies, intrigue and sacrifices on their journey to change destiny.