"Knock" is a science fiction short story about a mysterious camphor tree and an old woman. A giant camphor tree that must be several hundred years old grows in the big park near the protagonist's house. One day, the protagonist as a little kid sees a mysterious old woman standing before the tree. There she encounters an unbelievable scene. Author Arai Motoko emerged as a talent as a high school student, when she made her debut. Her science fiction and light novels weave together stories with unique buoyancy and bring a new sense of rhythm and fresh writing style to Japanese literature. She is recognized as one of Japan's preeminent science fiction authors. Delight in Arai Motoko's charming world with "Knock."