Helen, who embarks on a passionate affair with a man who has no idea what her secret identity is. Caught in the crosshairs when her lover falls victim to the dangerous London underworld, Helen's employer's call in Sam to protect her.
Cast: Keira Knightley, Ben Whishaw, Sarah Lancashire, Andrew Buchan, Andrew Koji, Omari Douglas, Sam Troughton, Ella Lily Hyland, Isabella Wei, Charlotte Rice-Foley, Taylor Sullivan, Finn Bennett, Tracey Ullman, Géraldine Chevalley, Kathryn Hunter, Gabrielle Creevy, Molly Chesworth, Ken Nwosu
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.
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.
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.
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.
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.
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.