In Tokyo, there is a neighbourhood with the highest number of bookstores in the world. It is called Jinbocho where book lovers can browse to their heart's delight and where hunters of first editions or autographed copies prowl the bookcases.

The Morisaki bookshop, a small family-run shop, is so packed with books that barely five people can fit inside. Books crowd the shelves and invade every corner of the floor; when a customer arrives, the owner, Satoru, immediately pops out from behind the counter. Recently, his wife Momoko has joined him, and often, in her free time after work, their niece Takako also helps out.

For the first time, the girl does not feel lonely; she has new friends and new rituals to keep her company: the annual Jinbocho festival, the café around the corner, or an unexpected visitor. Because, as she has discovered, a bookstore is populated not by the characters contained in the books, but also by those who frequent it. And those stories create bonds.

As a sign of gratitude, Takako gives her aunt and uncle a trip, promising to look after the shop while they are away. Everything seems to be going swimmingly, but then why is Satoru behaving so strangely? And what does that woman with the red umbrella want who has appeared at the end of the street? How many other stories, emotions, and treasures does the Morisaki bookshop hold?