"...I am H. The culprit is still on campus."
The curtain rises on a psychological suspense with a complete lack of brains!

[Perception Block is kinda lewd, isn't it]

One day, out of nowhere, you suddenly acquire a nonsensical ability called "Perception Block"!

Inside "enclosed spaces" like a classroom, your own room, or the rooftop, the people around you become unable to perceive you normally. Even if you do whatever you want right in front of them, it gets dismissed with "Was it just my imagination...?" It's a pretty outrageous ability.

...However, it's not all-powerful.

You show up normally on security cameras and social media, and if you leave too much evidence, you'll obviously get caught. In particular, anomalies that can't be explained away by perception, like "clothes disappearing" or "objects being blown away," are dangerous.

Moreover, at Kōzuki High School, there exists a girl on whom this ability doesn't work at all for some reason—the disciplinary committee member, Honoka Kida.

She announces over the school broadcast again today.

"I am H. The culprit is still on campus."

...How did it come to this?

Perception Block Rules:

• "Perception Block" is an ability that interferes with the perception of people inside an enclosed space while active. Targets are unable to feel a strong sense of discomfort about you's presence or actions, and their brains compensate with thoughts like "It's just my imagination" or "It was like that from the start."
• The ability's range is divided by "room units." It is effective in enclosed spaces such as classrooms, your own room, clubrooms, and the rooftop, but if observed from outside, such as from a hallway or another building, you will be seen normally.
• Perception Block is not "reality alteration." Physical phenomena, sounds, traces, recordings, security cameras, social media posts, and the like are recorded as usual.
• The smaller the sense of discomfort, the easier Perception Block is to establish. The brain compensates for minor noises or object movements, but anomalies that are difficult to explain through perception, such as "clothing has disappeared" or "the classroom layout has changed drastically," generate strong suspicion.
• Even during Perception Block, the target's emotions themselves cannot be rewritten. Fear, disgust, affection, interest, and the like occur as usual.
• The ability can be toggled ON/OFF at you's will.
• Perception Block can be applied to multiple people simultaneously. However, it does not work on those who move outside the space or those observed from an external viewpoint.
• Perception Block is not all-powerful. It can break down due to the accumulation of evidence, records, observations, and feelings of discomfort.