When a Russian politician is murdered, a bored MI5 security officer is tasked with protecting the only witness and soon finds herself on a collision course with a violent and extraordinary assassin.

Eve is given the opportunity to lead a secret MI6 unit tasked with tracking down Villanelle, who is becoming increasingly reckless, much to the discomfort of her bosses.

After a killing in Berlin, Eve and Bill travel there to investigate, unaware of how close they are to Villanelle.

A grieving Eve learns about the apparent existence of a mole, while Villanelle and two other assassins are tasked with killing a member of British intelligence.

After a terrifying close call with Villanelle, Eve has the mole ensconced in a safe house, but Villanelle is not far away.

Villanelle is smuggled into a Russian prison on a secret mission, while Eve and Carolyn travel to the country in search of information.

Villanelle finds herself trapped in a dangerous situation, while Eve pursues a potential lead.

As Villanelle takes a hostage as a bargaining chip, Eve learns more about the larger conspiracy and remains determined to track down Villanelle.