"Gentlemen's Alliance" is a manga series created by Arina Tanemura. It follows the story of Haine Otomiya, a girl who transfers to a prestigious all-boys school, Eikou Academy, where she aims to become the school's first female student council president. The series explores themes of friendship, love, and the challenges of gender roles in a unique setting. The plot centers around Haine's interactions with the school's elite male students, particularly Shinogu Otonashi, who becomes her love interest. As she navigates her new environment, Haine faces various obstacles, including rivalries and misunderstandings, all while trying to prove her worth in a male-dominated institution.