Night falls

Top mercenary K, seeking revenge for his tragically murdered sister, secretly returns to the country, only to unexpectedly save Tang Rou, the female director of the Haode Group, during a mission. This seemingly accidental encounter is actually the beginning of their intertwined fates. She needs his power to eliminate hidden enemies within the group, while he uses her resources to infiltrate the enemy's heartland, tacitly exploiting each other. However, when a common enemy surfaces, the two, forced to join forces, gradually lower their guard in a series of life-or-death battles, their relationship evolving from cold, calculating exchanges of interests to an unintentional blossoming of ambiguous feelings.