Yui carries the tragic past of losing her parents to the Samejima Group. Fueled by this hatred, she resolves to become an investigator and begins her mission to destroy the Samejima Group, the murderers of her family. However, as victims' families from a series of murder cases start disappearing under suspicious circumstances, Yui finds herself drawn into the Samejima Group's conspiracy. Around the same time, her childhood friend Yuko loses her fiancé to murder and then vanishes without a trace. Holding onto the grief of losing her family and her unwavering sense of justice, Yui continues her pursuit of the truth behind the Samejima Group.