Ore no Imouto ga Konnani Kawaii Wake ga Nai

Synopsis

When Ayase suspects Kirino is hiding something, she puts pressure on her and eventually discovers her hobby, telling her they can no longer be friends. Noticing Kirino falling into despair, Kyosuke resumes his life counseling duties and tries talking to Ayase, who says she wants to make up with her, but cannot accept her hobby having seen reports of crimes relating to eroge. Kyosuke asks for advice from his father, who helps him by giving the full story on those reports. Although Ayase still refuses to make up with Kirino after Kyosuke reveals the truth behind the news story, Kirino gains the courage to stand up to her and expresses her love for both her friends and eroge. When Ayase still has doubts about her hobby, Kyosuke puts on a bold act, which causes Ayase to hate him. However, Ayase realizes that her fight with Kirino is pointless in comparison and apologizes to Kirino for her harsh words. Shortly after, Kyosuke receives a text from Ayase thanking him for helping her and Kirino make up, though warns him not to do anything indecent to Kirino.

(Source: Wikipedia)