Empty first, first the text.
The storyline is a bit messy, the character relationships are a bit messy, and the time and space locations are a bit messy.
It tells the story between the princess who lost her country and the prince of the current dynasty. And the prince of the current dynasty happens to be the cousin of the subjugated princess, and this cousin's father happens to be the murderer of the subjugated princess. In short, the previous emperor was killed by his brother-in-law, leaving behind a subjugated princess. The current prince also had a soft spot for the subjugated princess, and a lot of love and hatred arose from this.