On the streets of downtown Seoul, people walk peacefully. Suddenly, withdrawal notifications simultaneously arrive from their electronic wallets. Soon after, the city's billboards are plastered with a hacker's warning message. 'You Know what? What can you do?' 'It's Better World.' 15 days before the incident! Among hackers, where there are no eternal winners or losers. Appearing like a comet, a genius hacker named Jaemin a.k.a. Hex, known as the overseer of hackers. Jaemin mastered hacking on his own to find the black hacker group 'You Know What' that drove his father's company to ruin, and was monitoring the movements of black hackers. One day, Jaemin detects suspicious hacker activity, and just as he tries to stop it! He is instead blocked by the white hacker group, 'Better World'.