Norn was researching the "Vessel of the King"—a concept Misia had mentioned—in the library. A Vessel of the King has no fixed estrus cycle but can enter a state of sexual arousal at will; furthermore, his semen compels females into a state of intense sexual arousal. Observing Misia’s own aroused state, Norn began to suspect that he himself was a Vessel of the King. In this world, males are scarce, so females are the ones who work to support their families. Since managing the housework alone was becoming too much for Misia, they decided to hire her childhood friend, Chise, as a maid. Chise arrived with a cute appearance—complete with fox ears—and Norn felt she was like a little sister to him. Norn found satisfaction in having Chise call him "Big Brother." Chise changed her clothes and began cleaning the house. Although Norn was slightly disappointed that she wasn't wearing a maid outfit, he found himself unable to suppress his arousal upon catching glimpses of her underwear beneath her skirt.