Royal Bell o Narashite

The setting is a poverty-stricken country known as Vinbona.

Although the heroine, princess Yuuri, has only steamed potatoes to eat as her meals, she's happy with her life, and everything is peaceful.

One day, a prince named Alt from the rich kingdom of Kanemotia appears, and Yuuri attends his birthday party instead of her father's. However, that ended up being a big mistake, as she doesn't want to return home.

To help try and bring Yuuri out of her sudden sadness, the king of Vinbona comes up with an outrageous plan--

"In order to remedy the financial difficulty in our country...
...you must marry one of the princes from Kanemotia!"

Will Yuuri be able to perform this duty safely, after sneaking into Kanemotia?