I Shouldn't Have Written That Novel

Hiiragi Sosuke has lived in this world for 13 years. Even though various things have happened during these 13 years, he is currently dragging his childhood sweetheart and unrelated sister to live in his mother's sister's house. Go to school during the day, go home from school in the afternoon to buy groceries and cook, wash the dishes after dinner and help my sister with her homework, sit at the desk in the evening and write a popular novel... Hiiragi Sosuke is sincerely satisfied with this kind of life. Until one day, the hero of the novel in military uniform appeared in his study. At that moment, Hiiragi Sosuke felt that something had disappeared from his life...