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.