Keira Knightley shows off her fighting skills as an action hero in the official trailer for Netflix thriller Black Doves that dropped on Wednesday. The series releases on Dec. 5.

A different turn from the period dramas (Atonement and Pride and Prejudice) that established her film career, spy series Black Doves features a badass Knightely firing guns and throwing punches as Helen Webb, a British agent whose cover is threatened when her secret lover is killed and she goes looking for revenge amid escalating gunfights.

“If you try to stop me, I will kill you myself,” she says at one point in the trailer. Webb has been passing on her politician husband’s secrets to a shadowy group, the Black Doves, and her spymaster (Sarah Lancashire) calls in an old friend (Ben Whishaw) to help investigate who assassinated her lover. That leads them into a vast, interconnected conspiracy linking the murky...