The movie which is based on the same-titled novel by Higashino Keigo that had sold more than 5 million copies, is set in modern Japan in the year 2012. Yamada plays the lead character Atsuya who grew up at an orphanage. After doing some evil deeds with his childhood friends Shota and Kohei, he hides at an abandoned house which used to be a general store named Namiya that was known for being a place where people could come to seek advice for their troubles. While at the house, Atsuya finds a letter written by someone 32 years ago in 1980 asking for advice on a problem in the post box and starts to interact with this person through mail on the behalf of the store's owner Namiya Yuji (Nishida). Gradually, the secret behind the store is unravelled through the mail correspondence. Kanichiro will be playing the role of Kohei in this movie.
Kanichiro who is 20 years old, revealed frankly that he doesn't like it when people mention his father but he knows that this link will no doubt bring more attention to him which he hopes to convert into something positive in his career as an actor. As such, he will try his best to work hard and become a good actor in future. Although Kanichiro has almost no experience in acting, the director decided to let him figure out how to play Kohei rather than issue specific instructions to him. As for the filming process, Kanichiro revealed that as he was working with actors around the same age as him, it was fun to be around them and the staff who tried their utmost to produce this movie.
Kanichiro actually told his father when he was around 17 or 18 that he aspired to become an actor but the latter simply said that he understood what Kanichiro wanted and didn't elaborate on what he meant with his simple answer.