My Little Sister and a Forbidden Room (妹と開かずの間) is the first episode of Eromanga Sensei anime series.
Masamune Izumi is a high school student that makes a living writing light-novels and lives alone with his younger stepsister, Sagiri, who has been a recluse holed up in her room for the past year. One day, Masamune hears from his classmate Tomoe Takasago that the mysterious illustrator "Eromanga-sensei" who draws the art for his novels has been ragging on him on the internet. Masamune ends up watching one of Eromanga-sensei's live stream and is shocked to learn who "Eromanga-sensei" is in real life--!?
The story begins with Izumi Masamune remembers his first encounter with his little sister, Izumi Sagiri when he sleep in front of his laptop after finishes his light novel. He describes his sister as fragile and states how she react when they met each other. When their eyes met, Izumi stunned because of her beauty and her behavior. But after that, he never meet his sister again.
His clock rings and Izumi wakes up and writhing. After that he makes himself breakfast and also to his little sister. Sagiri knocks the floor her room which indicates that she is hungry and ask Izumi to quicken his pace. Izumi respond that he will go there right away. Izumi left the meal and a piece of note that ask Sagiri to get out of her room so he can see her face in front of her door because she don't respond. After that Izumi go to school and leaves their house and before leaving the house, he take glimpse at her sister window.
On the way to school, Izumi introduce himself. He encounter Takasago Tomoe and they discuss about his light novel. Izumi tells that he always been fighting for his life. His sister always been shut herself in her room from an accident that kills their parent. His only wish is to see his sister face one more time.
At school, Izumi search his name at internet. While searching, Izumi narrates and says that he has been working with his partner who draws erotic pictures, Eromanga-Sensei. They has been working together about three years, since Izumi debuted as light novel author. However they never met each other before. Izumi held his first autograph session to commemorate completion of his series, The Silver Wolf's Reincarnation. He also shows his face at the session which brings curiosity to him as he thought maybe some of his classmates recognize him there. When you take a look at ambience, it seems no one notice him. Suddenly he find out that someone critics his signature at a blog.
In the Takasago Bookstore, Tomoe tries to console him as he disappoint of the critics. As Tomoe checks the post of the blog, she realize that the one who critics is Izumi's partner, Eromanga-sensei. Tomoe ask whether Izumi had done something to Eromanga-Sensei which he denied and explain that they never met and all the works been done by Eromanga-Sensei are sent by email.Upon checking the blog, they find out that Eromanga-Sensei going to make live streaming tonight. Tomoe suggest Izumi to check the streaming.
As Izumi arrived at his house, Sagiri knocks her floor's room indicates she is hungry and Izumi hurriedly make her lunch. While cooking, Sagiri knocks again and again. Then, he left her food in front of her room and asks her to put dishes outside the room when she done eating. He also write a note that ask her to tell him what food she want to eat.
At his room, Izumi turn on his laptop and checks the streaming. As the stream goes on, many comments pop out and Izumi felt a little jealous because Eromanga-Sensei can communicating with fans directly. Eromanga-Sensei seems a little angry because of her fan comments as perverted artist. After that, the streaming shows Eromanga-Sensei draws Beniusagi from The Silver Wolf's Reincarnation. During drawing session, Eromanga-Sensei stated that she disappointed with Izumi-Sensei for killing they favorite character. She critics Izumi-Sensei for killing her. While drawing, Eromanga-Sensei take a picture of they butt. She also apologize for her absent during autograph session because she can't show her face to public. A fan asks whether Izumi-Sensei is a high school girl and Eromanga-Sensei says they don't know. They also comments Izumi signature and make fun of it.