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--!?