Charlotte, a kind-hearted noble lady, is promised the most glorious future in her home country, the Grandia Kingdom. However, her life takes a turn for the worse when her father brings home her cousin Lily. To appease Lily, Charlotte's friends, family, and even her fiancé, the crown prince, turn against her. Driven to the fringes of the castle, she is abused and neglected. Just as she falls into despair, a wounded monster appears before her, offering to help her get revenge on those who wronged her. This is the story of a Japanese high school boy who reincarnates as a monster in another world, levels up, and gets revenge on those who wronged him. This novel is based on the author's short story, "The Opposite of Love is Indifference."