An older sister had her fiancé stolen by her younger sister, who was always unfairly taking away precious things. To avoid being banished to the frontier after breaking her engagement, she accepted a proposal from a marquis of the frontier who was twenty years her senior—a contract marriage. However...

"Cunning, cunning" — my younger sister, who always steals my things through her seductive wiles, deceived the Crown Prince, and he declared our engagement annulled! And he announced it publicly at a ball, no less. I was accused of sending poisoned cookies to my sister, but I never sent anything like that. However, they say a letter in my handwriting was attached to it... I was also accused of bullying my sister, and no matter how much I deny it, no one will listen to me. But then one man questioned whether it was appropriate for the Crown Prince to publicly annul his engagement to a duke's daughter over such accusations. And that man was a Margrave — a member of the royal family who is more than 20 years older than me.