(from ebookjapan):
A man is driven mad by the presence of someone lurking behind the ceiling, and gradually breaks down. Is it really an illusion created by the man? Or.... Yes, there is something mysterious lurking behind the ceiling.... And at night... Ever since she started living alone in an old one-story apartment, Mari, a female student, has been unusually lucky. She is so lucky that she herself feels insecure. Sub, a man who also lives in the apartment next door, has also had unnatural luck. One night, Sabu wakes up to the presence of someone walking on the ceiling...

Title one-shot is an adaptation of Ranpo Edogawa's short story.