Atsushi Hokari, Masato Kageura, Satoshi Mizukami, Ko Murakami, and Guest attend Mikado City First High School. Classmates in 3-C and Border agents, the five of them lived ordinary lives balancing school and duty.

Then, one day after school. A classmate suddenly tells the five of them, "Find my body." Because the words were spoken so normally, the five of them didn't think much of it and simply went home.

That night. After finishing a day like any other and falling asleep, the five of them wake up—to find themselves in a deserted school at night.

At first, they think it's a dream. However, as they walk through the school, they encounter Hokari, Kageura, Mizukami, and Murakami one after another. Realizing they are all in the same place, they understand this is no dream.

As the clock strikes midnight, something begins.

Without knowing what is happening, the five of them wander the night school building.

Then, the "Red Person" appears.

No matter if they run or fight, they are killed over and over. Yet, despite dying, the five of them wake up to the same morning again.

It is the exact same day as yesterday. And when night falls, they are back at school.

In this abnormal night that began without explanation, the five of them gather information little by little during the repeating day to face the nightly "Body Search."