Lao A's cross-border manhunt mission was ambushed. Yuan Lang and Xu Sanduo were trapped in a desperate situation. The blood marks on their palms became a life and death agreement for each other. In order to break the "Shadow Organization" behind the "Shadow", Xu Sanduo turned into a lone wolf and went undercover, sneaking into the enemy's lair as an "abandoned son"; Yuan Lang saw through the hidden secrets of his superiors and secretly followed and guarded him. The temptation and tacit understanding in the smoke, the trust and redemption in the desperate situation, when the true face of the traitor emerges, the old marks on the palms of the two people will eventually overlap - this is the blood contract of Old A, and it is also the heaviest bond outside of the smoke.
Purpose: two-way protection and perseverance of faith in the military context