Koshodo Monogatari

Set in a certain old bookstore, "Yume Neko", when the girls who visit there start reading a mystery novel recommended by the store owner, they travel back in time to the world of the novel, where the brutality unfolds. It also depicts the growth of a girl who finds answers to the troubles and conflicts that girls have in the real world by interacting with people they meet in the world of novels that have slipped back in time.
(Source: Japanese = mdpr.jp || Translation = MDL)