Cancer is a monster that you never saw coming. It's been two years since you lost Yejun-the love of your life and the father of your six-year-old son, Sujin. Yejun's last request was for his best friend to promise to take care of you and Sujin once he was gone, and that's exactly what Taehyung does to honor Yejun's memory, starting with giving you a letter.