Knightley's character Helen is a spy for a secret agency called Black Doves, which has no alliances but is contracted by the highest bidder. When Helen's lover is murdered, an old friend, Sam (played by Whishaw), who calls himself a “trigger man,” is brought in to protect her. He also vows to help Helen get revenge.

A group of operatives working for private espionage organizations attempt to prevent an international incident around the holidays, in a six-episode drama created by Joe Barton ('Giri/Haji').

Starring Keira Knightley as Helen Webb, a normal mother and wife who happens to be a professional spy, the limited series is set against the backdrop of London at Christmas, according to Netflix's description.