Synopsis of Volume 13:
A very simple high school student, Kousaka Kyousuke, has a beautiful younger sister named Kirino.
Kyousuke has made a great effort to protect the “secret” that Kirino was actually a beautiful Otaku girl.
During these days, Kyousuke finally meets Kirino’s best friend, Aragaki Ayase.
However, Ayase, who hates Otakus with all her heart, finds out about Kirino’s Otaku secret.
As a result, Kirino had a big fight with Ayase. After hearing Kirino’s “life advice” request, Kyousuke had to sacrifice himself and tell Ayase a big lie to protect Ayase and Kirino friendship.
Because of the lie Kyosuke told her, Ayase hated him. But one day, Kyousuke received an unusual request from Ayase regarding Kirino. No better person could resolve Ayase’s “doubts about Kirino” than the much-hated Kyousuke.
After several life advice requests for Ayase, the relationship between the two grew as Kyousuke continued to help her until Ayase finally learned Kyousuke lied to her so he could protect the relationship between Ayase and Kirino.
Ayase apologizes to Kyousuke, and a new relationship begins between them.
『I want to understand Kirino’s hobby.』
Since Ayase requested to learn more about Kirino’s hobby, Kyousuke took her to participate in the Summer Comiket.
After nearly meeting with Kirino and encountering trouble with Ayase’s classmate, Kanako, their relationship gradually improved.
During the Summer Comiket event, they met Kirino’s Otaku friend and Kyouske’s Kouhai, Kuroneko (Gokou Ruri), who saw Kyousuke and Ayase having fun together, which made her extremely angry.
The reason is, Kuroneko secretly admired Kyousuke, and since Kyosuke was studying for his university entrance exams, Kuroneko simply did not take a proactive approach to him. After her gentle heart broke, polluted by darkness, Kuroneko called herself “Yamineko,” the angel of revenge.
Finally, on her way back to the house after the Summer Comiket, Ayase confesses her true feelings to Kyosuke.
Kyousuke accepted her confession, and they became lovers.