One day, Nozomi, a second-year high school student, finds a love confession letter on her classroom desk. The sender is Setoyama, the most popular boy in school. While puzzled as to whether or not the letter is a prank, a secret exchange diary between the two begins when she puts her reply in the shoebox. However, the letter and exchange diary were actually meant for someone else - Nozomi's close friend. The exchange diary begins with a misunderstanding, but Nozomi continues to write to him without telling him the truth about her identity. And as she gets to know him, she becomes attracted to him. On the other hand, Setoyama loses more and more opportunities to confide in her, and the situation takes an unexpected turn... What is the fate of the painful unrequited love that started with a lie? (Source: Japanese = movies.shochiku.co.jp || Translation = MyDramaList) ~~ Adapted from the novel "Kokan Uso Nikki" (交換ウソ日記) by Sakura Iyo (櫻いいよ).