Engraved Pleasure

Robert, the prince of the Kingdom of Corinth, promised Arieno, the sole daughter of a farmer in his territory, - that he will enroll together with her in a military academy in two years. - However, soon after making the promise, Arieno goes missing. - Two years later, when Robert was about to head to the military academy, Arieno, who had become his servant, was waiting for him. - Why did Arieno suddenly go missing, and what happened during her two blank years? - Robert comes to know about this question through assignments at the military academy. - ​