Strawberry Panic! Girls' School in Fullbloom

The plot of Strawberry Panic! revolves around the lives of the adolescents who attend one of three affiliated all-girl schools which share a campus and dormitories. The schools are: St. Miator's Girls' Academy, St. Spica's Girls' Institute, and St. Lulim's Girls' School. There are twelve characters the story revolves around, four at each school. The story's main character is Nagisa Aoi, a young girl entering her fourth year at St. Miator after being transferred from another school. On first entering the campus grounds she is overcome with joy by the overall appearance of the surrounding area, but her joy is soon turned to sorrow as she accidentally stumbles down a hill, causing her to be lost and disoriented. While walking around the grounds trying to work out where she is, Nagisa comes across an older student named Shizuma Hanazono, who happens to be Astraea Hill's Etoile, a very important person who acts as a representative between the different schools and has specific duties that she must fulfill. Nagisa is instantly overcome by Shizuma's beauty, and after Shizuma kisses her on the forehead, Nagisa loses consciousness and awakens in the school's infirmary. In an adjacent chair is another girl of the same age, Tamao Suzumi, who informs her that they are to be roommates in the dormitory.

There are three playable characters, one from each of the schools: Nagisa, Hikari, and Kizuna. They have no family names in the game, as when the series of short stories were first published. While Ai Shimizu maintained her role for Kizuna in the game, Miyuki Sawashiro performed the voice for Tamao Suzumi. The game features a "boy mode" and a "girl mode". Choosing the male version means that the story is told via emails from the player's younger sister; choosing the female version means that the story is told in the player's own diary. The player is given the chance to pair their chosen character with one of the other nine available girls, not including the other possible playable characters. There are twenty-seven different combinations depending on which girl the player chooses at the start of the game.