In her senior year of high school, Baek Su Jeong starts playing an online game where she meets another player nicknamed “Black Dragon.” The two unexpectedly grew close, developed a crush on each other, and planned to meet in real life… which ended in humiliation and disaster when “Black Dragon” turned out to be a clumsy middle school student instead of the young man he had claimed to be! Sixteen years later, Su Jeong is a skilled planner at Yongseong Department Store, but her job is about to be turned upside down with the arrival of Ban Ju Yeon, the ambitious new head of strategic planning and heir to the company. There’s just one problem: Ban Ju Yeon is actually “Black Dragon,” and Su Jeong still holds a grudge against her. Will their past come back to haunt them, or will they manage to find a way to resolve their misunderstandings and even find love as adults?