As WWI ends, Kate Galloway moves to London after tragedy strikes but a fateful night leaves her with blood on her hands; Violet Davies fights for her place in the police force.

As Kate and Billie dispose of a body, the Saluccis' search for their missing heir; Violet is assigned to go undercover in the police cells where her skills and morals are tested.

As Kate and Billie set up their new club, Violet goes deeper undercover to find out the truth about Silvio. But opening night takes an unexpected turn when the Saluccis arrive.

As Kate becomes embroiled with the Saluccis, Billie and Evie seek solace elsewhere; Turner ups the ante on Violet, who makes an unexpected discovery during the club's reopening.

When key information behind Silvio's murder falls into the wrong hands, it sets off a dangerous chain of events for Kate and Violet; Evie tries to reconcile with her grief.

As the club prepares for a defining night, Kate finds unexpected allies in her pursuit of power; Violet seeks revenge for Lily; Billie weighs up her future.