Cotton 

One rainy day, the young woman Natsuki encounters a high school student in the street. Acting on an impulse, she gives the girl her umbrella and walks away. It turns out later that the girl, Michiko, is the younger sister of Natsuki’s sister’s newly-married husband. Even though Michiko has a difficult personality and doesn’t open herself to others easily, she seems to be attracted to Natsuki. Thus begins an unusual friendship between two unlikely characters who need each other more than they first realize. (Source: Kotonoha) Inlcudes bonus content/oneshots in 2010 reprint: Seibutsu (Creature) (生物) Asa no Kodomo (Morning's Child) (朝の子ども) Tegami (Letter) (手紙) Zange (Last days of summer) (残夏) telephone under the rose Houkago (放課後)