The genius Mitarai Kiyoshi is a neuroscientist and famous sleuth. The author, Ishioka Kazuki, is his good friend. One day, Ishioka starts to tell him about a mystery which he had heard on the radio. It is something that a listener had witnessed one day. A long-haired woman wearing a white dress was walking in the pouring rain with a closed umbrella. She held a small plastic bag in her hand and
