Yuma, a high school second-year, is enjoying every day now that she has her first boyfriend. After she asks for relationship advice from Hotaru, her beautiful long-time friend who has had many boyfriends, Hotaru teases her for her inexperience and playfully does things to her that even her boyfriend doesn't do. Yuma and Hotaru's secret relationship continues to escalate, and Yuma finds herself unable to deny how it makes her feel. This school drama tells the story of the interwoven lives of these two girls with boyfriends.
Nagisa Aoi is a new transfer student into one of the three prestigious all-girls Catholic high schools on Astraea Hill: a school called St. Miator (the other two are St. Spica and St. Lelim (known in the anime as Le Rim, for some reason). While getting totally lost on her first day, she stumbles into a clearing with a tree, and also into a girl with long silver hair. Nagisa is immediately smitten with the girl, Shizuma Hanazono, otherwise known as the Etoile of the three schools (the most idolized girl). Shizuma, after picking up a figurine dropped by Nagisa, kisses her on the forehead, leading to Nagisa fainting. After waking up in the school's infirmary, Nagisa then meets her new roommate, Tamao Suzumi. Things, however, will be getting a lot more complicated for the new student than just that.