Toshio is shocked by Megumi's sudden death from anemia and suspects something unusual, though her family refuses an autopsy. At her funeral, Natsuno distances himself emotionally, despite others trying to involve him. Toshio and his team find Megumi's condition rare and unexplained, and more mysterious deaths follow. Suspecting an epidemic, Toshio, Seishin, and councilman Ishida begin a discreet investigation. Meanwhile, Natsuno grows increasingly uneasy, feeling as though he's being watched.

Mysterious deaths continue in Sotoba, including Mikiyasu and his son. Toshio suspects an epidemic and investigates quietly. Natsuno is haunted by visions of Megumi. Seishin meets a strange girl named Sunako who can't go out in sunlight.