Yuzu, a high school gyaru who hasn't experienced her first love yet, transfers to an all-girls school after her mother remarries. She's beyond upset that she can't land a boyfriend at her new school. Then, on her first day, she meets the beautiful black-haired student council president Mei in the worst way possible. What's more, she later finds out that Mei is her new step-sister, and they'll be living under the same roof! And so the love affair between two polar opposite high school girls who find themselves drawn to one another begins!