In the 25th century, sexual intercourse and reproduction are prohibited, whereas use of Psychoactive drug is mandatory to enforce compliance among the citizens and to ensure their ability to conduct dangerous and demanding tasks. Emotions and the concept of family are taboo. Everyone is clad in identical uniforms and has shaven heads to emphasize uniformity, except the police android (robot)s (who wear black) and robed monks. Instead of names, people have designations with three arbitrary letters (referred to as the "prefix") and four digits, shown on an identity badge worn at all times.