Sekihan-chan to Sumomo-kun

Watari Maika has been in and out of hospital since she was little, and consequently missed out on most of her school life. Now about to start high school, she is determined to fit in with her new classmates and start from scratch with a high school debut, but manages only a short stay before she again falls ill and is forced to stay home.

Six months pass before she is able to return, just in time to visit the cultural festival, and as she'd feared, none of her classmates remember her ever having been there—exept for a rather tall, pretty maid with long hair she does not recognize. Watari is delighted to have found someone who remembers her, and immediately pleads for friendship—and now Shun Momoi has missed the timing to let the girl he fell in love with at first sight know who he is out of uniform.

(Source: MU)