Set in present-day Tokyo, Sherlock works as a freelancer crime consultant. From an early age, Sherlock has been fascinated with how people become criminals and in original sin. He is a genius, but he also has an impulse to commit crimes. Sherlock works on cases that interests him among police or customer requests. Meanwhile, Watson is a psychiatrist. He is smart and cool-headed. Due to a case, Watson gets involved with Sherlock. At first, Watson thinks Sherlock is ignorant and arrogant, but, as they work together, Watson gets comfortable with Sherlock.