The Red Apple.

The story happens in the near future of Japan, where sexual activity is forbidden by law. Inuda Hikaru is an honor student whose father is an executive at Setori (Sexual Misconduct Control Bureau of the Ministry of Health, Labor and Welfare). Hikaru aspires to become like his father and finds sex unpleasant. Minase Yu is Hikaru's childhood friend who has a sharp tongue but excels in her grades. Yu is also a big fan of nationally known actress Uchu Misora, commonly known as Uchura. One day, Hikaru is invited by a classmate to a shady members-only club where he witnesses men and women engaging in illegal sexual acts. He is also surprised to see Uchura, who claims to be "pure" there with a man. Before he realised, Hikaru finds himself being caught in an "underworld organization" where sexual activity is performed.