Keira Knightley is seeing double in her newest project, and it’s not just because of the mind-bending plot. In The Woman in Cabin 10, the two-time Oscar nominee dives into psychological chaos, murder, deceit, and a doppelgänger twist that even she didn’t see coming. The film, based on Ruth Ware’s 2016 novel, follows a journalist named Lo Blacklock who sets off on what’s supposed to be an easy assignment aboard a luxury superyacht. But what begins as a glamorous escape quickly unravels into a nightmare when Lo witnesses what she believes to be a woman being thrown overboard in the middle of the night.
The yacht belongs to a reclusive billionaire, Anne, played by Lisa Loven Kongsli, and her husband Richard, portrayed with cold precision by Guy Pearce. Surrounded by wealth, secrecy, and people who seem to know more than they admit, Lo finds herself alone in her conviction that something terrible has happened. Every passenger and crew member insists nothing is wrong, and Anne is supposedly alive and well, but Lo can’t shake what she saw. Her instincts tell her the truth is being buried beneath champagne flutes and polished decks.
Determined to uncover what really happened, Lo begins a relentless investigation, confronting evasive staff and suspicious guests. As she digs deeper, the veneer of luxury begins to crack, revealing something far more sinister than she imagined. The first half of the film builds a slow, taut suspense — the kind that toys with your sanity — and then, halfway through, the floor drops out. Lo discovers that it wasn’t some nameless woman who was thrown overboard. It was Anne herself.
That revelation detonates like a bomb, changing everything Lo — and the audience — thought they knew. Anne’s disappearance wasn’t an accident. Her death was the centerpiece of a plot meticulously crafted by her own husband. Richard, who can’t stomach the idea of losing control of his wife’s fortune once she dies, hatches a plan so elaborate and cruel it feels Shakespearean. He hires a woman named Carrie, played by Gitte Witt, to impersonate Anne. Carrie shaves her head to match the look of the ailing billionaire, rehearses her speech patterns, and prepares to pass herself off as Anne long enough to help Richard change the terms of her will.
When the yacht docks, Richard and Carrie plan to visit Anne’s lawyers and amend her estate in his favor, ensuring that he inherits everything instead of Anne’s chosen charities. But like most schemes built on greed and lies, it collapses under the weight of human emotion. Carrie never wanted to hurt anyone; she only agreed to pretend. But when Anne accidentally walks in on Richard and Carrie sharing a kiss in her cabin, a confrontation erupts. Words turn to violence, and in the heat of it, Richard strikes Anne, cracking her skull. Panic sets in, and rather than confess or seek help, he dumps his wife’s body into the ocean.
For Knightley, reading that twist for the first time was a genuine shock. She admitted she hadn’t read Ruth Ware’s novel before signing onto the project, so when the “Fake Anne” revelation came up in the script, it blindsided her. “I was like, ‘Gosh, I didn’t see that coming! F—— hell, how are we going to shoot that?’” she said, laughing. “And how are we going to get away with it? Are they going to have the same actress play Anne and Carrie, or will they be different actresses?”
The filmmakers quickly reassured her that two different actresses would be used — Kongsli as Anne, Witt as Carrie. Still, Knightley had doubts at first. “I met both of them while they still had hair, before they had their heads shaved,” she recalled. “And I was like, ‘What? They don’t look alike.’ But it was actually amazing, because as soon as they did have their heads shaved, you just don’t question it. It’s quite strange!”
That detail — the physical transformation that blurs the line between reality and performance — underscores the film’s eerie atmosphere. Everything in The Woman in Cabin 10 feels slightly off-kilter, like a dream you can’t quite wake up from. Lo’s paranoia mirrors the audience’s. You begin to wonder whether she’s imagining things, whether the events she’s recounting are even real. But when she finds proof of Anne’s intentions — a speech written for a charity gala, revealing that Anne planned to donate her entire fortune — the truth finally solidifies.
Armed with Anne’s speech and the knowledge of what really happened, Lo decides to confront Richard in the most public way possible. She sneaks into the charity gala where Richard, now pretending his wife is alive but “too ill to attend,” is basking in attention and sympathy. Lo storms the stage mid-event, exposing his crimes to the stunned audience. It’s a bold, reckless move, one that cements her as both a hero and a target.
The confrontation escalates quickly. Richard, cornered and enraged, grabs a knife and holds it to Lo’s throat. The moment is breathless — a desperate man clinging to the last remnants of control. But just as it seems he’ll silence her for good, Anne’s head of security, played by Amanda Collin, fires a shot that hits Richard in the shoulder. Lo, trembling but defiant, picks up a metal pipe and finishes what justice started. One brutal blow later, Richard is dead.
It’s a raw, primal moment that forces viewers to grapple with Lo’s moral line — or lack thereof. Did she act in self-defense? Or did she cross into vengeance? Knightley herself finds that ambiguity fascinating. “She figured out something was going on, so she went after corruption and managed to topple power,” she explained. “That’s who she is to her core, so I guess there’s satisfaction in the resolution. But it’s still pretty dark — she does kill him, after all. But to each their own!”
In the final sequence, Lo returns to her desk at the newspaper, back in her familiar world of words and deadlines. The newsroom buzzes around her as she reads her latest piece — an exposé on Richard’s empire and the accomplices now standing trial for their roles in Anne’s murder. There’s a flicker of satisfaction on her face, a quiet acknowledgment that she survived not just physically, but morally. She toppled the powerful and brought truth to light, though it cost her a piece of her soul.
That closing moment feels both triumphant and haunting. Lo gets her story, but at what price? Knightley’s performance carries that tension beautifully, balancing Lo’s relentless drive with the exhaustion of someone who’s seen too much. She’s not a perfect heroine — she’s flawed, human, and occasionally reckless — but that’s what makes her compelling.
Critics who’ve seen early screenings of The Woman in Cabin 10 have praised Knightley for grounding the story in emotion rather than spectacle. While the movie delivers its share of twists and suspense, its true strength lies in the psychological unraveling of its lead. Lo’s determination to find the truth, even as her own sanity is questioned, gives the film a slow-burning intensity that lingers long after the credits roll.
Knightley’s fascination with stories about complex women isn’t new. Throughout her career, she’s gravitated toward roles that explore moral gray areas — characters who defy easy labels of “good” or “bad.” From Atonement to The Imitation Game, she’s built a filmography full of women fighting for agency in worlds that underestimate or undermine them. Lo Blacklock, with her stubborn courage and emotional vulnerability, fits perfectly in that lineage.
For Knightley, The Woman in Cabin 10 isn’t just another thriller. It’s an exploration of truth, corruption, and what happens when one woman refuses to be silenced. The story’s setting — a gleaming yacht isolated at sea — becomes a metaphor for privilege and moral decay. Everyone on board is trapped, both physically and ethically, in a space where appearances matter more than humanity. Lo, as an outsider, pierces that illusion with the one thing money can’t buy: integrity.
The film also plays with the theme of identity in ways that feel particularly modern. Carrie’s transformation into Anne blurs the boundary between self and imitation, forcing viewers to consider how much of identity is performance. Knightley admitted that even on set, it was unnerving to watch Witt transform into Kongsli’s character through the shaved head and body language alone. “It really messes with your head,” she said. “Because at a certain point, you start to forget who’s who.”
That sense of disorientation — of seeing double — is central to the film’s power. The more Lo learns, the more the world around her distorts. The truth is constantly shifting, and every revelation comes with new moral consequences. Even after Richard’s death, there’s no clean sense of victory. There’s relief, perhaps, but not peace.
Knightley found that ambiguity satisfying. “I love that it doesn’t tie everything up neatly,” she said. “It’s dark, it’s messy, and it’s human. Lo doesn’t walk away unscathed — and I think that’s what makes it real.”
From a filmmaking perspective, The Woman in Cabin 10 marks a stylish evolution for the mystery-thriller genre. It trades jump scares for psychological tension, replacing cheap shocks with the slow, suffocating dread of knowing something’s very wrong. The ocean itself becomes a character — vast, silent, and merciless. The sound design amplifies that isolation, with creaking hulls, whispering waves, and the hum of engines blending into a constant, oppressive reminder of how far from safety Lo truly is.
And then there’s Knightley’s performance, which anchors all of it. She plays Lo with a raw, lived-in authenticity that makes her fear palpable and her victories earned. Even in the moments when she’s trembling, she radiates a quiet determination. Her Lo isn’t fearless — she’s terrified — but she pushes through it anyway. That, Knightley believes, is what heroism really looks like.
“There’s something incredibly empowering about watching a woman who’s scared but refuses to back down,” she said. “Lo’s not trying to be perfect. She’s trying to be brave, and that’s much harder.”
The film’s production also presented its own set of challenges. Shooting on water, recreating the claustrophobic interiors of a yacht, and coordinating complex night sequences all added to the tension. But Knightley said the environment helped her sink deeper into the role. “It’s physically disorienting,” she explained. “You’re constantly moving, even when you’re standing still. You never feel grounded. That sense of imbalance became part of Lo’s psychology.”
When asked whether she related to her character’s relentless pursuit of truth, Knightley smiled. “I think I do, actually,” she said. “Lo’s whole thing is: something doesn’t add up, and she won’t let it go. That’s a very journalist thing — but it’s also a very human thing. When something doesn’t sit right, it eats at you. You have to dig.”
Dig she does — and in the end, it’s that tenacity that defines both Lo and the film itself. The Woman in Cabin 10 doesn’t just tell a story about murder; it tells a story about the cost of knowing too much, the danger of power, and the courage it takes to face what others would rather ignore.
For Knightley, it’s another reminder of why she continues to be one of the most versatile and fearless actors working today. She doesn’t just play characters — she inhabits them, flaws and all, giving audiences something messy and real to hold onto.
And perhaps that’s why The Woman in Cabin 10 feels so haunting. It’s not just a mystery solved; it’s a moral reckoning. It’s about a woman who looks into the darkest corners of wealth, corruption, and deceit — and refuses to look away, even when the truth stares back like a reflection she barely recognizes.
By the time the credits roll, Keira Knightley’s Lo Blacklock has seen too much, survived too much, and changed too much to ever go back to who she was before she boarded that yacht. And maybe that’s the point. In a world built on illusion, sometimes the only way to find yourself is to lose everything else — even your innocence — along the way.