Yuzu Aihara is a captivating and fashionable young lady ready to embark on a quest for true love at her new all-girls school. However, there's a twist – the school is exclusively for girls. Despite this hurdle, Yuzu remains steadfast in her efforts to create meaningful relationships and make a positive impression. On the first day, she makes a great effort to present herself in the best light possible. Unfortunately, her efforts don't bear fruit, and she finds herself in a bind with the beautiful yet stern student council president, Mei, who takes Yuzu's phone. This leaves Yuzu in a state of confusion and unsure if she can enjoy high school as she hoped. The biggest shock comes when Yuzu arrives home to discover that Mei is her new stepsister. It gets even more complicated when Mei leans in for a kiss, sending Yuzu's heart racing and emotions spiraling out of control. She begins to question if she has any romantic feelings for Mei. Trapped between her role as a stepsister and her conflicting emotions towards Mei, Yuzu becomes determined to get closer to her. The question is, can Yuzu get through the walls Mei has built around her heart and help her confront the pain she's harbored for too long?