The protagonist, Kiritani Haruto, a 35-year-old socially awkward virgin, works as a librarian at a school where he is generally avoided and considered creepy by most students. Recently, his only solace comes from interactions with busty high school girls who engage in the "library attendance" system, a unique arrangement where students can avoid regular classes by studying in the library. The girls tease and mock Haruto, but secretly harbor a fondness for him, using the library time to confide in him about their troubles. Despite the awkward dynamics, the girls find ways to subtly enjoy moments of intimacy with Haruto while maintaining a facade of taking jabs at him in public.

[Translated from the official site]