Based on the novel published by Ikkunsya Iris NEO. コーデリア, a countess who was discriminated against because of her beautiful sister, has been betrayed by her sister, parents, and ex-fiancé. Giving up on love and marriage, she unexpectedly finds favor with the second prince, Leonhart, who dotes on her. Leonhart, who seems to have a strong ancestral reversion of the lion spirit, the ancestor of the royal family, is uncontrollably drawn to Cordelia, comparing her to catnip. While Cordelia refuses his advances, her sister's sudden closeness to Leonhart forces her to take action. This is a story about a lady who has captured the heart of a prince who can transform into a beast.