Rookie detective Izumi Sakuragi is assigned to the "Suginami Case," a kidnapping and murder from six years ago that holds a painful history for her colleagues, Nagashima and Takamine. A man named Oguri confesses to the crime, but while his handwriting and the blueprints he provides are a match, his voice isn't. Section 4 must now determine if Oguri is the real killer or if he had an accomplice.