The premise sounds like a punchline, but the show commits to the awkwardness with actual comedic timing. Keita's resistance crumbles in real time as he stops pretending he doesn't want what his sisters are offering, and that slow surrender is funnier than any setup could be. The fanservice isn't window dressing here, it's the entire point, and the show knows it well enough to make you laugh instead of squirm.
Keita's life takes a chaotic turn when his older stepsisters, the twins Ako and Riko, confess their romantic feelings for him after a mishap at school. Since they share no blood relation, the twins see nothing wrong with pursuing their affection, but Keita remains uncomfortable with the situation. He wants to keep things strictly sibling, even as he studies for his entrance exams to attend the same high school as them. The sisters help him prepare, but they also kiss him, flash him and show their love openly in public, and Keita slowly finds himself attracted to them, which he dislikes himself for at first. His parents only complicate matters by encouraging him to marry one of the two someday, and the twins are not the only women with designs on him. The result is an ecchi romantic comedy built on slice-of-life household chaos and embarrassing public moments.
