Among the many trends shaping contemporary television, few have become as persistent as the fascination with morally ambiguous protagonists. In recent years, audiences have grown used to following characters who lie, manipulate, and kill, often without the narrative fully condemning them. Sweetpea fits squarely within that tradition. The series does not attempt to reinvent the genre or introduce a radically new concept. Its interest lies in observing what happens when someone who seems ordinary, invisible, and deeply frustrated finally decides to push back against a world that has long ignored her.

The story centers on Rhiannon Lewis, played by Ella Purnell, a young woman whose defining experience is being constantly underestimated. She works in a routine office job, lives a largely solitary life, and carries the emotional scars of years of bullying and humiliation. Nothing about her daily existence suggests danger. If anything, Rhiannon appears to be exactly the kind of person who passes unnoticed in any room.

That invisibility becomes the core of the narrative.

For years, Rhiannon has learned to swallow her frustrations. At work, she is overlooked, in her personal relationships, she is rarely taken seriously, and in public, she often becomes the target of casual cruelty or small everyday humiliations that those responsible barely register. The series carefully constructs this accumulation of microaggressions that may not appear dramatic on their own but slowly erode the character’s sense of self.

The rupture comes when a series of particularly painful events pushes Rhiannon across a line she never imagined crossing. In a moment of emotional collapse, she commits murder.

This is the first major turning point in the series.

The crime is not the result of a calculated plan or the work of a brilliant criminal mind. It happens in the middle of a surge of anger and accumulated frustration. What surprises Rhiannon is not only the act itself, but the realization that no one around her even considers the possibility that she could be responsible. Because she is invisible, she is also invisible as a suspect.

From that moment on, Sweetpea begins to explore two parallel narrative threads. On one level, we watch Rhiannon trying to maintain her apparently normal life while dealing with the consequences of the crime. On another, we follow the psychological impact that the murder has on her. Rather than descending into guilt or remorse, the character begins to experience something she has never felt before: a strange sense of control.

That discovery changes the dynamics of the story.

What began as an impulsive act gradually turns into a recurring behavior. As new tensions emerge in her life, Rhiannon begins to consider violence as a possible solution. Each new crime forces her to manipulate situations, hide evidence, and create plausible explanations for suspicious events. Much of the series unfolds through this tension between the attempt to preserve the appearance of normalcy and the steady escalation of violence.

One of the key turning points arrives when Rhiannon realizes that killing not only resolves certain immediate problems but also gives her something she has never had before: power. People who once ignored her now, unknowingly, orbit a far more dangerous version of her. At that point, the audience begins to understand that the series is not simply following someone who reacted to injustice, but someone who starts to discover pleasure in this new position.

The cast helps sustain that ambiguity. Ella Purnell carries the series with a performance that balances vulnerability, irony, and an increasingly unsettling moral shift. Rhiannon is not portrayed as a criminal mastermind or a cartoonish villain. For much of the narrative, she remains a seemingly ordinary young woman who has made terrible decisions and must now live with them. Among the other members of the cast are Nicôle Lecky, Calam Lynch, and Leah Harvey, who populate the social world around the protagonist and often function as mirrors of the tensions that surround her.

Sweetpea also has a literary origin. The series is based on the novel of the same name by C. J. Skuse, published in 2017, which introduced readers to the diaries of Rhiannon Lewis, a narrator whose voice combines dark humor, resentment, and violent fantasies. The television adaptation retains some of that sharp irony but shifts the focus toward a more conventional thriller structure in which suspense revolves around the possibility that the protagonist may eventually be exposed.

The season’s ending plays precisely with that tension.

Throughout the episodes, clues accumulate, suspicions begin to surface, and the risk of exposure grows. Some characters come dangerously close to the truth, while others start to sense that something deeply unsettling lies beneath Rhiannon’s quiet exterior. Yet the series ultimately refuses to offer a simple resolution. The protagonist manages to avoid immediate consequences and maintain the façade of an ordinary life.

The real conclusion, however, is psychological.

At the beginning of the story, Rhiannon is someone crushed by her own insignificance. By the end she has become someone who has discovered a distorted form of power. The final image suggests that this transformation is only beginning. There is no sign of redemption or genuine remorse. What remains instead is the unsettling realization that for someone who has spent an entire life being invisible, violence can become a way of finally existing.