After committing a burglary, Atsuya (Yamada Ryosuke) and his friends Shota (Murakami Nijiro) and Kohei (Kanichiro) run into the abandoned Namiya General Store and decide to hide there for the night. Suddenly, a letter comes in through the mail slot. The letter is written by a woman in the past seeking advice for her problems. From old clippings, the three youths learn that years ago the general store's owner used to provide advice to troubled souls, leaving his reply in a milk box outside the store. On a whim, the boys decide to write a reply to the mystery letter and deliver it in the same way. Thus begins a long and magical night as letters keep coming in, and the boys gradually realize that their replies are affecting and connecting lives, including their own.