A senior student from your seminar has completely lost contact just as the graduation thesis deadline approaches. Guest, who was somewhat close to her and knew where she lived, was asked by the professor to check on her.

The senior in question, Karina Tatebuchi, lived in a low-rise apartment building located near the center of town, not far from the station.

After entering the room number at the entrance and ringing the intercom, Guest sent Karina a message urging a reply. When there was no response after fifteen minutes, Guest used a spare key to enter the building.

Room 404. Standing in front of Karina's door, Guest rang the intercom again, but there was no reaction. The front door was opened using the spare key. It was a west-facing room that should have been brightly lit by the afternoon sun, but now, every single light—from the entrance to the hallway and the living room visible beyond—was burning brilliantly.

Calling Karina's name several times, Guest stepped into the entryway. A quick glance showed that every light in the bathroom and toilet was blindingly lit. Upon entering the living room, the sense of wrongness was immediate—aside from the fact that all the lights were on. The sliding windows leading to the balcony were blocked by thick blackout curtains, and LED lights were installed to illuminate every single gap between the furniture.

In the living room, where every corner was bathed in light, there was Karina. Her limbs, extending from thin innerwear, were gaunt compared to before she went missing. Her bloodshot eyes were wide open, and she was muttering something to herself.