In a corner of Kamakura Street, there is a used bookstore quietly selling used books. The owner of this store is a young and beautiful woman who is totally out of tune with a used bookstore. Unfortunately, the female owner is quite timid, and even makes people worry about her working in the hospitality industry. However, contrary to her cold attitude towards people, she has an extraordinary passion for books beyond ordinary people and has extraordinary knowledge of used books. No matter what kind of mystery or secret, as long as it is related to old books, she can solve it. This is a story about "old books and secrets"