University student Hirose Kiyotaka finds a love letter tucked into the pages of a borrowed book. While attempting to return the letter, he encounters the charismatic Hanashiro Seiji and quickly becomes involved with him. As their tentative relationship develops, however, he finds himself wondering how serious Hanashiro's feelings for him really are. Meanwhile, the letter falls into the hands of Hanashiro's colleague Sawa Jinichiro, who entraps its writer, Arihara Mineo. Sawa's actions are seemingly ruthless, but his true motives regarding Arihara are far from clear. (Source: SuBLime)

Yagi-san Yuubin was published digitally in English as Lost Letters by SuBLime on August 27, 2013 to January 25, 2017.