Zero Day Attack summary: A skilled hacker, Jin Kang, falls into a broker's trap and fails his mission. Barely escaping with his life, he can't bring himself to face VX, a genius hacker and team member he greatly respects. Instead, Jin Kang chooses to go into hiding. By day, he works at a café, while at night, he quietly plots his revenge. However, his routine takes an unexpected twist when a mysterious and striking customer, Seo Yiyeon, enters the café and makes bold advances toward him. Baffled by Yiyeon's unexpected attention, Jin Kang now finds his plans for starting to go awry...