A love triangle between me, who is indifferent to romance, my younger sister who loves romance, and His Royal Highness the Crown Prince who doesn't want to break off his engagement.

I'm always being troubled by my younger sister, and she proposed that I hand over my fiancé, the Crown Prince, to her. It was an engagement decided by our parents, and since I had been causing trouble due to my sister's love of men for some time, I answered that it would be fine if she settled her romantic entanglements. My sister agreed, but the Crown Prince said he couldn't go along with this proposal. I thought I was being unreasonable and tried to back out... but then the Crown Prince told me he wanted to break off our engagement... And it seems my sister is involved in this somehow.