Michael King (played by action star Song Il Gook) is a secret agent and a billionaire with one goal in his life: to seek revenge against the men who killed his parents. Having grown up with adopted parents in the States, he returns to Korea to haunt the murderous group, who are all now wealthy and powerful. His partner and girlfriend Vivien (Han Go Eun) betrays him while he conducts his revenge, and Michael is forced to turn to an unlikely ally: reporter Jin Bo Bae (Han Chae Young). Based on a popular manhwa, this high-flying, action drama even went on location in Hawaii to film several episodes.