When politician's wife and undercover spy Helen Webb learns that her lover has been murdered, the Black Doves recruit an old friend to help protect her.

After reaching a dead end in the search for Jason's killer, Helen has to fight for her own life, while Sam receives a threat from his former employer.

Memories of Sam's past come back to haunt him as he prepares to finish the job he started seven years ago. Wallace secretly meets with a Chinese envoy.

Investigations into the ambassador's death reach the highest corridors of power. Helen pays a risky visit to an old friend, and Sam faces a tough choice.

With danger drawing closer, Sam takes refuge in the only safe place he knows. Reed issues an ultimatum, and Helen gets one step closer to the truth.

Armed with evidence and bent on vengeance, Helen goes searching for the Clarks. As the conspiracy starts to unravel, she has a deadly decision to make.