In Vienna, a brunette woman (Villanelle
) sits in a cafe eating ice cream as a young girl seated at another table watches. The waiter and the girl exchange smiles. The woman smiles at the girl who smiles back. The woman checks the time (5:05) and gets up to leave. She tips the waiter before knocking over the girl's ice cream bowl into her lap on her way out the door.
In London, Eve Polastri screams in her sleep. Her husband, Niko, wakes her up and Eve tells him it was because she fell asleep on both arms. She has a headache from staying out late the night before and singing karaoke with her co-workers for her boss, Bill's, birthday. Even though it is Saturday, she has to go into work at MI5. At the office, Elena Felton explains to Eve on the way to the meeting that a Russian sex-trafficking politician was murdered in Vienna.
Eve enters the meeting late and sits down next to her boss, Bill Pargrave. Frank Haleton introduces everyone to Carolyn Martens who runs the MI6 Russia Desk. Carolyn informs them of the assassination of Victor Kedrin, a high-profile Russian politician. He was leaving a sushi restaurant near Stephansplatz with his girlfriend, Kasia Molkovska, when his femoral artery was sliced open. The girlfriend fled the scene and was picked up in Hammersmith. Eve and Bill are to provide diplomatic protection for Kasia. Eve tells Carolyn that it was a woman who assassinated Kedrin.
In Paris, Villanelle rides the subway, her hair now blonde. She exits the subway and walks to her apartment. She encounters her neighbor, Madame Tattevin, leaving the building and they exchange heated words. In her apartment, she puts away a wig and toiletries and takes off the camisole that she had worn to make herself appear flat-chested. She admires herself in a mirror and powders her face white. She pours some pills onto her coffee table and lays supine on her couch with a bottle of alcohol, playing dead. A man (Konstantin) enters the apartment and tells Villanelle that he can see her breathing. She asks if he'd be sad if she were dead and he says, "of course." He is there to deliver her a bonus and give her information on her next job tomorrow in Tuscany. He leaves and Villanelle sits down at her laptop to decrypt the information off the Tuscan postcard she received.
At MI5, Eve finds out from Elena that Kasia is still at Hammersmith station and decides to go visit her. Bill tells her that CCTV revealed it was a man who assassinated Kadrin but he hasn't actually seen the tape. Eve leaves to interview Kasia, who is on drugs and speaking incoherent Polish. The translator is unable to understand her, besides the assassin being a "plank."
Eve visits Niko at his Polish bridge club and recruits him and a Polish teenager, Dom, to listen to the recording of Kasia's babbling about the assassination. They decipher that Kasia is using slang and the assassin was tall, dark, and flat-chested, a "small-breasted psycho." Eve calls Elena at the office and requests information on Margit Polsen and any other active female assassins under the age of 45. Margit's breasts are too big for it to have been her and the other two female assassins (Katrina Voltrinski and Wendi Helmsen) are dead.
Villanelle rides a motorcycle through Tuscany and arrives at an estate. She pins her hair back into a bun and sets off across the vineyards to the main house. She climbs up a drainpipe and sneaks inside. There is an anniversary celebration going on outside and she spots her next target, Cesare Greco. She hides in a suitcase to avoid being caught before going down to join the party, wearing a dress she stole from Greco's wife. She follows Davide, Greco's grandson, back into the house and convinces him to play a trick on his grandfather.
Davide calls his grandfather up to the house and hides as Villanelle waits for Greco in his bedroom. She asks him about the bedspread and he says that it is made by Liliana Rizzari. She tells him her name is Syliviana Morel and she has been sent to him. She removes the hairpin and stabs him in the eye before depressing the plunger to inject him with poison. She gets a pen from the desk and writes down Liliana Rizzari onto her palm before watching Greco die. She leaves just as Davide comes out of his hiding place to find his grandfather dead.
Eve is impressed with the murder of Kedrin from a tiny puncture wound and asks Niko how he might kill her. Niko says he might push her down the stairs or flatter her to death. She tells Niko she would paralyze him with saxitoxin and suffocate him in his sleep, chop him up, boil him down, put him in a blender, and then flush him down a restaurant toilet. Later, as they're going to bed, Eve questions whether or not the CCTV recording is real. Niko tells her she should have been a spy.
Konstantin wakes Villanelle up in her apartment where she is sleeping with a man and a woman. Kasia is in London and will be interviewed tomorrow as a witness to Kedrin's murder. Villanelle's train leaves in an hour and she is meant to make Kasia's death look like a suicide.
Eve and Bill share lunch together while Eve tries convincing Bill that Kedrin's assassin was a woman and there is a cover up with the CCTV. Eve has been compiling cases for months, including Greco's murder, that were done by a new and prolific female assassin. Bill tells her to go to the hospital to make sure Kasia is secure and then go home.
Eve takes Dom with her to the hospital and has him pretend to be Kasia's relative. While they are waiting to speak with Kasia, Eve goes to the restroom where the one stall is in use. While she is waiting, she fixes her hair. Villanelle exits a stall dressed as a nurse and watches Eve, prompting Eve to ask if she is all right. Villanelle stops on her way out of the bathroom and tells Eve to wear her hair down. While Eve is using the toilet, Bill calls to tell her that there was no CCTV and she needs to keep Kasia safe. Eve returns to the hospital room to find the nurse and the security detail are dead. She tries to stop the bleeding from Kasia's throat but Kasia dies as Dom returns with snacks.
Bill sits with Eve and tells her she did the right thing. Frank and Carolyn enter and Frank blames Eve for conducting an illegal investigation, manipulating a witness, putting a minor in danger, and failing to protect Kasia. Eve confronts Frank about the assassin being a woman and Frank fires her. Eve and Bill both call Frank a "dick-swab" and Frank fires them both.
Eve is at home watching television with Niko when her doorbell rings. Carolyn invites her to walk to the corner shop where she reveals to Eve that Villanelle has been operating for two years across ten countries. She offers to buy Eve breakfast on Thursday at 9 am at the Purple Penguin by Charing Cross.
Villanelle unpacks her new bedspread from Liliana Rizzari and lays down on it as she reviews a postcard for Bulgaria.