The Mizuhanome System is a remarkable invention that grants individuals access to the most fascinating place on earth - the human mind. By utilizing "cognition particles," left by wrongdoers at crime scenes, Kura detectives can generate a virtual reality of the criminal's unconscious thoughts, called "id wells," to identify the culprit. Nonetheless, not everyone can enter the id wells as it requires having committed murder. Having fallen from grace due to a tragedy that rocked the police force, Akihito Narihisago, aka "Sakaido," meets this criterion. Incarceration aside, Narihisago leverages his exceptional sleuthing skills to aid Kura. However, the deeper he delves into the investigations, the more he realizes that there is something far more sinister lurking beneath the surface of these seemingly unconnected homicides.