After bumping into his little sister, Kirino, in the hall, Kyōsuke Kōsaka finds a magical girl anime DVD which contains a little-sister themed adult game inside. Kyōsuke soon learns the game belongs to Kirino and confronts her about it.

Noticing Kirino has no one to share her hobbies with, Kyōsuke asks for advice from his friend, Manami Tamura, who suggests that she make some otaku friends.

Kirino hangs out with Saori and Kuroneko again and is surprised to find that they do not have to worry about hiding their hobbies.

When Kirino forces Kyōsuke to play a beat-em-up eroge, he asks Saori for some playing advice.

Kirino's best friend Ayase, finds out that she likes eroge.

Manami invites Kyōsuke over to her house to try out some sweets made by her family's shop for a Halloween event.

Kirino drags Kyōsuke around the city on Christmas Eve.

While Kirino's novel becomes increasingly popular, her editor reveals that it may be adapted into an anime.

Kirino gets a long awaited adult game in the post and spends the entire day playing it.

Ayase asks Kyōsuke to give her advice on a present she can give Kirion to make up with her.

After running into her at the supermarket, Kyōsuke invites Manami over to his house to help him make lunch.

Kirino uses her final life counseling session to ask Kyōsuke to buy her an adult game that is launching at midnight in Akihabara.