My Friend's Little Sister Has It In for Me!

Akiteru Oboshi keeps a low profile at school while managing a small creative circle called the 5th Floor Alliance. His only close friend is Ozuma Kohinata. Ozuma’s younger sister Iroha spends time at Akiteru’s place and needles him in private while acting like a model student in class. Akiteru’s uncle offers funding if Akiteru agrees to a formal relationship with his cousin Mashiro Tsukinomori. Mashiro is a quiet classmate and a secret bestselling author. The deal forces Akiteru to juggle club deadlines, staged dates, and the risk of hurting people he cares about. Iroha aims to become a voice actor and helps the group in secret because her family disapproves. Projects for a culture festival and a game demo bring late nights, staff shortages, and rumors that complicate every promise Akiteru makes. A strict teacher with a hidden pen name and other classmates add pressure. Misunderstandings give way to simple truths as the circle delivers its work and Akiteru starts to face what he actually wants.