The Grand Duke of the North is a kitten…? Melody, a maid in the Grand Duke’s household, named a kitten Lucky that she happened to rescue on the street. They spent peaceful days together, sleeping every night. However, one morning, Lucky, who used to sleep with her every day, was nowhere to be found. Instead, she was nestled in the broad arms of Grand Duke Calsius! To make matters more intriguing, he strictly forbade any disclosure of the incident, transformed into Lucky before her eyes, and ran away. ‘A cute kitten like Lucky is the Beast of the Snow.’ For a moment, Melody was bewildered by the dignified Northern Grand Duke’s unexpected appearance. Because Melody found out his secret, she was forcibly incorporated into a secret organization, where she took on the role of a fake mistress and a cure for his insomnia… The problem is, later on, she could face execution for treason, and even the workers were destined to share the same fate. If she’s his mistress, she’s no different from the main member of the treason plot. “Assist him? Forget that, I’m going to escape!”