Takagi (Mamiya Shotaro) and Sonoko (Araki Yuko) were classmates in Class 6-1. After a class reunion, the two find themselves embroiled in a serial murder case targeting six people who have a connection to Sonoko. In order to prevent the next murder, they head to the home of one of the targets, Emi (Matsui Rena), also known as "Nico-chan." Emi, who works as a hostess in Roppongi, apologizes to Sonoko upon their reunion, but... She will never forget... What is the connection between Sonoko and Emi? Can Takagi stop the serial murders?