My Sister is a Raunchy Big-Breasted AV Actress 2

Yuuki Rin is a brilliant fourth-year university student who leads a double life as an AV actress—a fact she hides from her cousin Michiyasu, with whom she's now dating with marriage plans. Her younger brother, Isao, a second-year student living with her in Tokyo, discovers her secret through her films and becomes consumed by conflicted feelings as he watches her carry on an intimate relationship with their cousin while secretly performing in adult videos. The story unfolds through the brother's perspective as he navigates jealousy, voyeurism, and the tension between family bonds and sexual desire.