Mamahaha no tsurego ga moto-kano datta 7 Mo Sukoshi Dake Kono Mama de (Kadokawa Sneaker Bunko) [Light Novel]

[Machine Translation] Mizuto and Yume, who became siblings after their parents remarried, are former lovers. After the school festival, their memories of being an ex-couple are becoming good memories... Yume is the secretary of the student council, and a new routine has begun! She steps into the student council room with a nervous look on her face, and what she finds is a group of high school students who are surprisingly sensitive about love! Yume, who has been sarcastic with Mizuto for a long time, finds it hard to tell him that she likes him, but she takes a hint from the love stories of the other female members, including the president, Beni-Rinri, and comes up with a "devilish move" to get Mizuto to confess his feelings for her. The first time she does this, Yume is surprised to find herself in the middle of a fight with a girl she has never met before. On the day they greet each other as siblings, their feelings face each other...?

親の再婚できょうだいになった水斗と結女は、元恋人同士。文化祭の一件から、元カップルだった記憶もいい思い出になりつつある秋のこの頃...結女が生徒会書記を務める、新たな日常も始まっていた!緊張の面持ちで足を踏み入れた生徒会室に集うのは―意外と恋に多感な高校生たちで!?水斗と散々嫌味を言い合った手前、いまさら好きだと言いにくい結女は、会長・紅鈴理はじめ女子メンバーの恋バナをヒントに、水斗から告白させるための“小悪魔ムーブ”を思いつき!?「―私たちの、誕生日。予定、空けておいてね」そしてきょうだいとして迎えるその日に、二人の想いは向かい合う―?