[Machine Translation] Only a few people in the Tokyo Metropolitan Police Department know that Makoto Doyasu has a twin brother. The brothers play a dual role in the "Supervisory Investigation Unit," which secretly investigates crimes committed by members of the same family, to uncover wrongdoings. One day, the head of an automated driving experiment under the government's jurisdiction is killed in a building crash. The day before, someone had killed another person involved in the experiment, but the police ruled it a suicide. Suspicious, the two head for the test site. This is a police novel in which a unique buddy plays an active role.