Eventually you will hear about a bookstore opening up at the mall (station mall) called the Bookworm. There it is run by an old couple, before you visit the store I suggest you go to the persimmons tree located at the school (at the entrance go to the right hallway and enter the doorway right next to the staircase, the tree is through there). At the tree you will find a leaf and you will need to take it to the old couple. You will hear them talking about it and you will give it to them, they will be so touched you will gain a social link with them.