Zeikin de Katta Hon

Synopsis

From Kodansha: Ishidaira is a delinquent who visited the library for the first time since elementary school. But then, he was pointed out by Hayasemaru and Shirai, who works at the library, that he has not returned a book that he borrowed ten years ago. A manga about how Ishidaira went from trying to borrow a book from a library to working there instead.