In a modern metropolis with a thriving economy and tangled social conflicts, gleaming skyscrapers conceal undercurrents in gray areas beyond the reach of the law. Surveillance cameras cover 75% of the city, and facial recognition is widely used. Yet in this supposedly "transparent society," a mysterious serial killer moves with ease through the gaps between law and technology, committing a string of chillingly perfect crimes. His targets are people who have committed serious offenses, including rape, murder, corruption, and drug trafficking, yet remain at large due to a lack of evidence or loopholes in the law. Before each crime, he anonymously sends out a "judgment letter" detailing the target's crimes and the evidence against them. Often, this evidence is more comprehensive than anything the police have uncovered.
