The story follows Sasaki, an exhausted and undervalued high school teacher struggling with mounting stress from his daily work. One night, while staying late at school, he encounters a bizarre supernatural phenomenon: the students shoe lockers have transformed into glowing selection panels. Directed by a mysterious announcement welcoming him to the Guilty Hole, he jokingly selects a female student on a whim. To his shock, she appears before him in the classroom in the middle of the night, acting embarrassed yet compliant. This event marks his initiation into a strange, dreamlike dimension where forbidden relationships with his students are not only permitted but orchestrated by an unseen force.

The protagonist, also referred to as Koki Nishiyama, is an overworked and underpaid educator who is easily manipulated by his students and feels resentful toward his job. His internal conflict is central to the narrative, as he struggles between his moral boundaries and the desires unleashed within the Guilty Hole. His primary student partner is Amai Miruku, a girl who initially insults him but whose gaze betrays a mix of shame and longing. Other students become involved as the story progresses, including Chiyoki Remon, the class representative who responds to his sincerity in her own way, and Kanna Natsuki, a dark-skinned gyaru who offers him comfort. Each encounter explores different dynamics and emotional vulnerabilities. The setting alternates between the pressures of daily school life and the surreal, nocturnal dream dimension where the Guilty Hole manifests, taking forms such as the classroom, the nurse's office, and even the protagonist's own home.

The narrative is structured in episodic arcs, each triggered when the exhausted teacher falls asleep and is pulled into the Guilty Hole. Early episodes establish the basic premise, such as his first encounter with Miruku and later unlocking the ability to request specific girls like the glasses-wearing class representative. As the series progresses, new rules are introduced, including an option feature that allows for reverse nominations where the students take a more active role. A significant shift occurs when it is revealed that the female students are also experiencing the same shared dreams, leading to growing tension and jealousy among them during school hours. This development blurs the line between fantasy and reality, forcing the protagonist to confront the consequences of his actions in both worlds. The story culminates in scenarios where he must face multiple students simultaneously, as the original sin of his selections begins to unravel and affect his waking life.