"True love doesn't perish." Houmoku Chikaku's suicide – the year has passed and by January the third semester has begun. Kagome Seishin Girls Academy is shook by a particular event: The election of the new student council administration team is imminent. First year student of the Bird Class, Mashiro Hii, is lending a friend, Suoh Tamaki, her supportive hand during the election process. One day, Hii meets a girl called Tsubaki Tsukumo, the supposed sister of the former student council's vice president Tsubaki Shijuuku who has now disappeared. In order to seek out the truth, Hii confronts the residing student council president, Rindou Tsui, with the question whether she's the murderer of Houmuku Tooku, the twin sister of the late suicide victim Houmoku Chikaku. Tsui is ready to let her in on the truth if a certain condition is fulfilled – they agree on a bet. A bet about which candidate will succeed in becoming the next student council president. Hii reluctantly accepts. "Should I win this bet, I want you to fall in love with me." [Translated with anecdotal information added from the [url=https://www.dlsite.com/home/work/=/product_id/RJ240372.html]DLSite[/url]]

籠目聖心女学院。 それはさながら少女たちの花園、子羊たちの楽園。 春から高等部に上がる『竜胆 終』。 彼女は母から、 一学年上の先輩・生徒会執行部長『祈緒 綴』の暗殺を命じられる。 期限は一年以内。 それまでに事を成し遂げられれば、 竜胆家・座敷牢に幽閉されている『終の双子の姉妹』―― 彼女の解放を赦すという。 かくして新年度。 『竜胆 終』は、 『祈緒 綴』暗殺を成功させるべく行動を起こす――