Katsuji Chuudokusha no Mahon Tansaku, Aruiwa Ura Toshokan no Koto: Mahotan

One day, Kaho, a bookworm, opens the door to the Secret Library and accidentally releases "magical books" that take on a life of their own. Taking responsibility for her actions, Kaho becomes the head of the Secret Library Committee, which oversees the unruly collection. Together with Hayama, also a member of the Committee, she sets out to find the characters who have escaped from the pages of the books. What secret do these strange fugitives hold?