Widow Tong Suk Fan has raised her two sons, Yau Ching and Yau Kit, through years of hardship. Now grown, both brothers proudly serve in the Anti-Terrorist Force—one in Intelligence, the other in Operations—earning the respect of their boss and bringing pride to their mother.

But when a secret investigation puts them on opposite sides, their strong bond begins to unravel. Yau Ching, tipped off by journalist Yip Ting, uncovers a hidden threat and is nearly killed while digging deeper. Forced into hiding, he secretly continues his search with help from his girlfriend, intelligence analyst Yat Ka, and discovers a mole may be hiding within the agency.

As Yau Kit starts to suspect his brother and grows closer to Yat Ka, Yau Ching finds unexpected support—and love—in Yip Ting. With the truth buried under layers of deception, Yau Ching must decide how far he’s willing to go, even if it costs him everything.