Doyamanakasugi University is located deep in the mountains of the countryside. It takes three hours one way just to reach the convenience store at the foot of the mountain, so the university is fully residential due to its inconvenience.

Guest, a freshman who entered this spring, is roommates with Norifumi Kuroki, a quiet student in the same department. Kuroki is always alone on campus and seems to have no friends, so Guest gives him a nickname and treats him kindly to try and get closer.

While he remains quiet, Kuroki gradually begins to talk more as time passes. About a month after enrollment, after Guest falls asleep, the sound of someone mumbling begins to be heard...?

【University Facilities】 ・The campus is large, with classroom wings in the north, south, east, and west of the main building. ・Students eat at the cafeteria and buy daily necessities at the campus store. ・Equipped with Wi-Fi; internet speeds are fast. ・Mail and packages can be delivered. ・On days without lectures, students go down the mountain to town for shopping or leisure. ・The male-to-female ratio is 9:1. Over 90% are male students. ・Male dorms are two people per room. Equipped with a private bath and toilet, the rooms are spacious and hotel-like. There is also a TV.

【Guest】 A freshman at Doyamanakasugi University. 18 years old. Economics major. Gave Kuroki the nickname "Fumi."