Sweetpea is a limited series for Sky Atlantic in the United Kingdom and Starz in the United States, which premiered on October 10, 2024. the series focuses on Rhiannon Lewis (Ella Purnell), who is constantly overlooked but harbors a killer secret. The series is based on the books by C.J. Skuse.

Although the series was released weekly in the United States and on broadcast networks in the U.K., it was released a binge-watch on the streaming services NowTV and Sky Go in the U.K. While originally announced as a limited series, on December 3, 2024, it was reported that Sweetpea had been renewed for a second season.

Sweetpea contains examples of the following:

• Adaptational Nice Guy: While she's still a serial killer, the show's Rhiannon still isn't nearly as psychopathic as her book counterpart. Rhiannon in the original novel is incapable of relating to other human beings for the most part, with an addiction to murder causing many of her victims to suffer particularly savage deaths.
• Aloof Big Sister: Seren spends most of her time ignoring her little sister Rhiannon and even their father. When they reunite at their father's funeral, Seren is more interested in reconnecting with high school friends than her sister and is incredibly callous and insensitive about selling the house Rhiannon is in but doing so with her old school bully.
• Alpha Bitch: Julia Blenkingsopp, Rhiannon Lewis's high school bully who continues to ooze contempt and still heads a clique even after growing up and becoming a high-powered real-estate agent.
• Arc Words: "People I'd love to kill..." followed by a list of names or types of annoying people.
• Asshole Victim:
  • Rhiannon targets "bullies" like a man harassing her (who also turns out to have a restraining order against him for falsely accusing a man of being a pedophile, nearly ruining his life just for his amusement) and a predatory landlord.
  • Marcus, who's a domestic abuser. We see how bad his abuse gets when Julia shows Rhiannon her scars from him, and when he begins to victim blame Julia after finding her tied up.
  • Subverted with Julia. At first, she seems to be the worst of the bunch, but it's soon revealed that she was neglected by her parents and married an abusive spouse, making her much more sympathetic.
• Awful Truth: AJ is horrified when Rhiannon confesses she'd committed the murders after he learns her knife is the murder weapon, right after having sex with her.
• Bathtub Scene: Rhiannon lets Julia have a bath after knocking her out and realizing she had gotten her period. The two chat as Julia bathes.
• Beneath Notice: Rhiannon notes that other people don't notice her much, due to being a very quiet, shy, petite young woman. As a result, once she's become a Serial Killer nobody suspects this at first.
• Berserk Button: Any slight is this for Rhiannon, especially making her feel like she's not seen.
• Beware the Quiet Ones: Rhiannon Lewis is the girl that everyone always overlooks and bullies, and turns out to become a serial killer.
• Blackmail: Craig coerces Rhiannon into selling him her father's business with the threat of revealing she asked him to lie for her, and this would be incriminating with the recent murders.
• Bolivian Army Ending: The last episode ends with Rhiannon having stabbed AJ to death, cradling his body as her sister Seren walks through the front door.
• Bullying a Dragon: Julia Blenkingsopp continues to be insulting and dismissive towards Rhiannon, even as she has her tied up with a knife to her throat, and knowing that she's already killed two people. Luckily for her, Rhiannon only seems interested in killing people and not otherwise maiming or hurting them, otherwise, she might have found herself in quite a bit of pain.
• Bully Turned Buddy: After the Frame-Up, Julia and Rhiannon become closer, with the pair going clubbing and talking on the rooftop the following morning. Subverted when Julia acts distant towards her after her interview at the Gazette and skips town using Rhiannon's bank card.
• Carpet of Virility: AJ is shown to have a pretty hairy chest when when he and Rhiannon have sex, which enhances his sexiness while he gets shown in a more masculine way.
• The Cassandra: Marina knows Rhiannon is really the Serial Killer, but her boss refuses to believe it. After she gets the evidence proving this, it's inadmissible due to her breaking into Rhiannon's house and getting it without a search warrant.
• Catchphrase: Throughout the show, Rhiannon's is "People I'd love to kill," followed by a list of people and the reasons why. This is eventually borrowed by Marina when she starts suspecting Rhiannon is behind the murders.
• The Chain of Harm: Julia tells Rhiannon she bullied her due to feeling bad about herself, and passing this on had made her feel better as a result. She points out that Rhiannon has, in turn, hurt people and made herself also feel better by doing so.
• Chekhov's Gun:
  • Rhiannon's dad's lock knife that she uses to commit her murders. She uses it as part of the plan to frame Marcus and it ends up in evidence. AJ's contact ends up sending of photo of it to him, and having been the only one to see the knife, he quickly puts the pieces together.
  • In Episode 6, Rhiannon shares her bank details with Julia so the two can go clubbing. Later on, Rhiannon finds a charge on her phone for an airplane ticket.
  • The knife that Rhiannon is using to chop vegetables when AJ shows up at her house is the knife that she uses the next morning to kill him when he realizes that she's the serial killer.
• Chekhov's Gunman: Played with in regards to Seren. She is shown early on, but spends most of the series just sending messages to Rhiannon about selling the house. Her threats of going to the house to settle the situation personally pan out in the series' Bolivian Army Ending.
• Cliffhanger: Episode 6 ends on one. Not only are Julia's whereabouts unknown, with it being heavily implied she's fled Carnsham, but Rhiannon has stabbed AJ to death after he sees her knife in police custody, with her sister Seren walking through the door as Rhiannon cradles AJ's bloody corpse.
• Coming and Going: The morning after Rhiannon and AJ have sex, he realizes she's the Serial Killer, and she murders him to cover it up.
• Commonality Connection: Rhiannon sees how Marina, one of the police detectives, gets ignored by her boss, who only notices Marina's partner. She has a moment of bonding with Marina by saying people don't see her either too much.
• Cradling Your Kill: Rhiannon tearfully cradles AJ after she stabs him to death, claiming she's not really a monster.
• Cruel and Unusual Death:
  • Rhiannon's first victim, Ryan, is stabbed fourteen times in his chest, arms and legs. The first stab is right to his neck too, which results in a massive blood spurt.
  • Jeff is pancaked thanks to a garbage truck while getting chased by Rhiannon.
• Cute and Psycho: Rhiannon may be quiet and petite and played by the very cute Ella Purnell, but she also extremely resentful, angry and murderous.
• Domestic Abuse: Julia's boyfriend Marcus is a classic domestic abuser, abusing her both physically and mentally, but when she tries to pull out, turning sweet and doing things like telling her he can't live without her and threatening to commit suicide if she leaves him.
• Enemies List: Rhiannon makes a list of the people who make her feel invisible, as well the ones she wants to kill. These may end up being one and the same. Marina does the same, as shown in Episode 3.
• Extreme Doormat: Rhiannon initially is very submissive and quiet, with other people often barely aware of her. She's walked over by her boss, her sister and basically everyone else due to this, while her dad urges that she stand up for herself. It's due to the severe bullying Rhiannon suffered by Julia at school, which left her with very low confidence. Finally though she starts to break out of this... but not in a good way.
• Foil: Marina is one to Rhiannon. They both internally monologue about who they'd like to kill throughout the series, but whereas Rhiannon is clearly quite serious, Marina's Enemies List is merely a morbid fantasy.
• Frame-Up: Julia agrees to frame Marcus, her abusive fiancé, for kidnapping her and as the Serial Killer so she's free of him while Rhiannon can be cleared.
• Freudian Excuse Is No Excuse: Julia thinks that Rhiannon's using Julia's bullying as an excuse to commit the murders.
  Rhiannon: What, you think I chose this?
  Julia: Ta-da.
• From Nobody to Nightmare: Rhiannon is never seen and walked over by EVERYONE. She eases her way into a nightmare by the end of the first episode. 
• Girl-on-Girl is Hot: Julia kisses Rhiannon at the club while partying drunk, with Craig watching and obviously turned on through seeing it.
• Grew a Spine: Rhiannon begins as a very shy, submissive person. Becoming a Serial Killer inspires much more confidence in her, as she gets more assertive and stands up for herself.
• High on Homicide: Rhiannon thinks very fondly of her murders while she's having sex.
• Idiot Ball: When AJ realises that Rhiannon is the serial killer, instead of just getting out of her apartment (where he’s looking for the knife), he tells her that he knows it’s her, giving her an opportunity and motive to murder him.
• In Vino Veritas: Marcus' true negative feelings toward Julia are revealed when he's drunk, after he'd made out when sober that they had a loving, perfect life together.
• Inconsistent Spelling: Closed-captioning sometimes gives Marina's last name as "Farrow" and sometimes as "Farrar."
• Incurable Cough of Death: An awful cough is the only obvious sign of anything actually wrong with Rhiannon's father, Tommy, who is well enough to prank her by pretending to be dead in his hospital bed. Nevertheless, a few minutes later, he is actually dead and the next scene is Rhiannon on her way to his funeral.
• Insistent Terminology: Rhiannon says she's an administrative assistant, not a secretary, but it's clear this only matters to her as a distinction.
• "Just Joking" Justification: Julia Blenkingsopp's excuse for a four-year campaign of bullying Rhiannon Lewis to the point of her tearing out her own hair, having to wear a wig, and feeling like a ghost is that it was just a joke. She later admits that it was really because Rhiannon had everything she didn't and she was jealous of her.
• Lingerie Scene: Rhiannon strips to her underwear when she and AJ have sex.
• Making Love in All the Wrong Places: Rhiannon has sex with Craig at his workplace as he's sitting on a chair in his office.
• Minority Police Officer: Both the police detectives investigating the murders Rhiannon's committed are people of color. Marina's black and Rory's South Asian. They're among only a few characters of color on the show, which is set in a mostly white town.
• Missing Mom: It's mentioned at the start than Rhiannon's mother walked out on them when she was a child and has since made no effort at all to reconnect with her daughters.
• Mistaken for Gay: As a result of them drunkenly kissing and growing quite close suddenly, Craig believes Rhiannon’s getting involved with Julia, though neither is really queer. Rhiannon is just amused by it.
• Nepotism: It's clear that AJ gets made junior reporter largely as the boss likes his mother. Rhiannon is furious at this and calls him a "nepo baby" angrily afterward.
• Nervous Tics: Rhiannon has a tic of pulling out her hair due to her trauma from being bullied by Julia Blenkingsopp - this resurfaces in the premiere when Julia returns to town, Rhiannon's sister having hired her as the estate agent to sell their home, and she sees a billboard featuring her.
• Never Speak Ill of the Dead: Rhiannon and AJ learn the first man she'd killed terrorized a work colleague, to the point of getting a restraining order out against him for stalking. There's reluctance initially to publish this, as he's a murder victim but Rhiannon's relieved learning he'd been a vicious bully and so that makes her feel better at killing him, and the story's published, which she defends when his distraught mother comes complaining.
• Nice Guy: AJ is an overall pleasant guy, being the only person at the start of the series to actually acknowledge Rhiannon's existence and treat her kindly.
• Nobody Suspects the Woman: Everyone assumes the killer simply must be a man, due to the combination of vicious attacks and the sheer trauma inflicted to the bodies. This allows Rhiannon to completely slip under the radar or any kind of suspicion, even during official police investigation.
• No Periods, Period: After knocking her out, Rhiannon sees Julia's gotten her period and bled through her pants. Later, she's allowed Julia to take a bath and gives her a tampon.
• Passed-Over Promotion: Despite actually being a good reporter, Rhiannon is passed over for a coveted junior reporter position at her job at the Carnsham Gazette in favour of AJ.
• Pet the Dog:
  • Jeff derides Rhiannon regularly and calls her promotion to junior reporter "box-ticking," but when Ryan's mother comes by the Gazette to call out AJ and Rhiannon, furious about the story exposing his restraining order, Jeff takes the credit to take the heat. Downplayed, however, in that he still takes credit for their story.
  • Rhiannon shows sympathy to her first victim Ryan's own bullying victim Dave, empathizing with him and assuring him he didn't deserve what happened to him. While it's partly to convince herself she was justified in killing him, she does seem to have genuine sympathy upon hearing his plight and being reminded of her own time being bullied by Julia.
• Psycho Knife Nut: Rhiannon's more than a bit unhinged, becoming a Serial Killer who kills people using her dad's old knife.
• Saying Too Much: Rhiannon repeats a phrase she used referring to the knife before, reminding AJ it was hers after he's learned about it being the murder weapon.
• Shout-Out: Rhiannon is showing gleefully watching the graphic throat-slitting scene from Eastern Promises.
• Sympathetic Murderer: Rhiannon becomes a Serial Killer, but her victims are always unpleasant somehow, and she had only started killing after suffering multiple tragedies in succession, which lets her stay sympathetic to a degree.
• Tagline: "It's always the quiet ones."
• Tampering with Food and Drink: After Jeff steals all credit for the story which Rhiannon researched with AJ, she spikes his coffee with milk of magnesia to make him sick in retaliation.
• Tempting Fate: Rhiannon insists, mostly to Marina after the latter finds the CCTV footage, that she's done with killing. Sure enough, come the end of that very episode, she's killed again.
• Title Drop:
  • Rhiannon's nickname from her boss is "Sweetpea" (he never uses her name at first). Fitting her character, it's all but stated she hates the nickname but doesn't say anything.
  • Each of the episode titles is something said by one of the characters. Julia tells Rhiannon "Sorry For Your Loss" in regards to the death of her father. Rhiannon tells her boss Norman that "This Sort of Thing Needs Some Feminine Energy" when petitioning him to go interview the family of her first murder victim. Rhiannon tells Julia that she found "Black Spots in the Garage" of her home, that she thinks they might be mold, as a means of luring her in there before trying to kill her. The members of Julia's clique, interviewed about her disappearance, tell Rhiannon that "Everybody Loves Julia."^note Though, technically, the exact wording used in the episode itself is that "everyone loves Julia." Jeff tells Rhiannon that Julia's fiancé Marcus has been telling him some things about her, that "Someone's Been a Naughty Girl." Finally, Rhiannon tells Julia that they're free to start their lives over now, that it's "Life 2.0."
• Trauma Conga Line: Rhiannon has gotten mistreated by most people or else at best ignored, then her dad dies (the only exception), her bully returns to her life (opening up old wounds which caused her Extreme Doormat personality), then her sister decides to sell their family home (in which she's still living) against her protests, her dog is killed and she finally snaps, murdering a man (while it initially starts out as self-defense) after having been pushed too far at last.
• Villainous Breakdown: In the final minutes of the season finale, AJ realizes that the murder weapon is the same kind of knife he saw Rhiannon use to open letters when they first met, making her the murderer. He rebuffs every attempt at an explanation and calls her a monster, driving her into a panicked state and causing her to kill him. The show ends with her cradling his stabbed, bleeding body while whispering to herself that she is not a monster.
• What Happened to the Mouse?: After Jeff is hit and killed by a garbage truck in the penultimate episode trying to bike away from Rhiannon after learning she is the killer, it is as if his character simply vanishes from the plot. None of his co-workers at the Carnsham Gazette in the final episode seem upset or worried by his death apart from a quick glimpse of a small mural of flowers and his photograph. Apart from that, he is never even mentioned once.