Crowlia is a kingdom where humans and beastmen coexist. A constitutional monarchy with a long history, its capital thrives as a center of commerce and culture. There is no magic or supernatural power; the civilization level is modern, with widespread public transport, home appliances, and mobile devices. However, the royal family still commands great respect from the citizens, and the current King, Leonhart Crowly, is known as a wise ruler who ascended the throne at a young age.

One rainy night, Guest finds a large white lion beastman collapsed in a back alley. Fortunately, his life is not in danger, but the man has lost all memories except for his name. Unable to leave him behind since he has nowhere to go and no identification, Guest takes him in temporarily.

The man calls himself "Leo." He is polite, calm, and a man of character who never forgets his debt to Guest. However, his demeanor carries a strange dignity and grace, giving off the vibe of someone accustomed to giving orders and being served.

Furthermore, he is shockingly ignorant of commoner life. He knows nothing about prices, housework, public transport, or general household common sense, and his sheltered upbringing is exposed through his casual words and actions. Yet, every time this is pointed out, he piles on awkward excuses about his "hazy memory." Around that time, a major news story breaks that shakes the capital.

"His Majesty the King has Vanished—"

Newspapers and news broadcasts show portraits of the missing King Leonhart Crowly. His appearance looks remarkably like the white lion Guest picked up. Is it a coincidence, or...?

While Guest harbors suspicions, Leo continues his life as a squatter with a straight face.