After receiving a box with a loaded gun, surgeon and family man Dai Huan encounters an attacker and pays dearly for following his conscience.

With their son's life at risk, Dai Huan and Tao Lu meet a man who knows the game well and track down the Watchers, who raise the stakes.

Betrayed by someone close to him, Dai Huan devises an intricate scheme to give his tormentors a taste of their own medicine.