After his father remarries, Yuuta Asamura finds himself living under the same roof as his attractive new stepsister, Saki Ayase, who happens to be the most popular girl in his school. Despite their shared history of parental divorces, they decide to maintain a respectful distance. Surprisingly, they discover common ground and gradually develop a close bond, raising questions about the nature of their growing feelings – whether it's mere admiration, familial affection, or something deeper.