I Fell in Love With My Cool FWB but She Brought Her Big Breasted Sister Over

A harem romantic comedy visual novel following Kosuke, a university student who becomes friends with benefits with Sana, a cool and initially expressionless woman. As they spend more time together, Sana begins showing increasingly cute emotional reactions, and Kosuke falls in love with her. When they move into a new apartment to split rent, Kosuke discovers that Sana's busty hostess sister Aira is also moving in—and she has her own agenda, regularly interrupting their intimate moments. The game features investigation mechanics to uncover plot details and hints, along with multiple intimate scenes as Kosuke navigates the complicated dynamics between the two sisters.