After retiring, the world's strongest assassin lives a secluded life in the city, only to have a chance encounter with a beautiful CEO. The CEO unexpectedly invites him to be her personal bodyguard—they eat, travel, and even live together. However, the CEO is surrounded by danger. With his superb skills, Leo Sutton easily resolves every crisis, causing the CEO to secretly fall for him. In the end, he wins the beauty's heart.
