After retiring, the world's top assassin, Leo Song, struggles to find a job. He unexpectedly meets Evelyn Shen, the beautiful CEO of Shen Group, and is invited to be her personal bodyguard. Because she possesses the 'Dragon Chip' technology, Evelyn Shen is repeatedly targeted for assassination by her competitors. Leo Song uses his top-tier skills to resolve one crisis after another. The two develop feelings for each other as they spend their days together. In the end, Leo Song wins her heart.