The Seventh Republic has not seen sunlight since the last great war, and its shadow-drenched streets breed crime with ease. Detective Ruka Hiryu of the infamous 13th Division — known as the Sideliners and treated with contempt by the rest of the force — has been quietly investigating the sealed Cult Massacre case. When two new members join the unit and rumors of the semi-mythical Shining Union begin to circulate, the already-unstable NPA is pushed toward a breaking point.