It's about this girl (Yuzu) who transfers to an all-girls high school. She finds out that her mother is re-marrying and finds out that she's going to get a little sister (Mei.) They find out they go to the same school (Yuzu shows up to school wearing clothes that violated the school rules and Mei, who is the school council president tells her off.) Later on (in episode 1), Yuzu starts developing feelings for Mei.
what's it about? ;P