In the vast Souren Empire, there reigned a beautiful young Emperor who ascended the throne at an early age.

With his refined features and noble bearing, the people praised him as a celestial being, and the court revered him as the ideal monarch. The Inner Palace was filled with numerous consorts selected from across the land—daughters of prestigious nobles and relatives of powerful figures, the finest women the nation had to offer. However, despite the years that had passed since his coronation, not a single prince or princess had been born to serve as heir. Furthermore, the consorts of the Inner Palace were in good health, and regular examinations showed no major abnormalities. While there were rumors of the consorts competing for his favor, the fact that no child was conceived remained an inexplicable mystery. With the positions of the Four Ministers—the highest ranks below the Empress—remaining vacant for a long time, the court's anxiety regarding the succession grew louder by the day.

The lack of an heir was not merely a family matter for the royals. Should the Emperor fall ill or meet with an accident, the stability of the nation itself could crumble. Consequently, the Prime Minister decided to look beyond the palace walls and invite the most brilliant doctor from the capital to the Inner Palace. The doctor chosen for this task was Guest.

Guest worked as an obstetrician-gynecologist at a large hospital in the capital. A genius physician who had mastered advanced medical and pharmaceutical knowledge at a young age, Guest was known for resolving numerous difficult cases.

Though not of noble birth, Guest possessed extraordinary medical insight and observation skills, famous for uncovering causes by listening to patients and meticulously examining their physical condition and living environment.

Suddenly tasked with this monumental duty, Guest was ordered to examine the consorts and find out why no heir was being born.

Though bewildered by the sudden summons to court, Guest accepted the duty as a physician. Upon entering the Inner Palace, Guest began checking the health of each consort, reviewing medical histories, menstrual cycles, lifestyle habits, diet, and medications. Guest investigated possibilities the court physicians had overlooked, systematically ruling out medical causes.

However, the more Guest investigated, the stranger things became. No major issues preventing pregnancy were found in any of the consorts. The results were the same across the board. The court, which initially assumed the problem lay with one of the women, was forced to reconsider. Thus, Guest turned the investigation toward the Emperor himself. It was determined that the Emperor's own health needed a thorough examination. However, the Emperor showed an extreme aversion to being examined. The Emperor appeared to be the picture of health, with no issues in his daily life. Court physicians had never noted any major illness, and his physical abilities were beyond reproach. Yet, as a doctor, Guest harbored doubts. There were many healthy consorts in the Inner Palace. And yet, not a single one was pregnant.