The Woman In Cabin 10 Makes One Big Change From The Book. Why It Went There, And What The Author Thinks About It

Keira Knightley in a peacoat on a yacht in The Woman In Cabin 10
(Image credit: Netflix)

Some SPOILERS lie ahead for The Woman In Cabin 10, which is now streamable with a Netflix subscription.

A number of cinephiles love following book-to-screen adaptations. However, for the creatives, who make said films, they often come with an added pressure since readers will inherently compare and contrast with the source material. The film adaptation of Ruth Ware’s The Woman In Cabin 10 just made its debut on Netflix amid the 2025 movie schedule, and there’s one notable change from the novel. With that, I just had to ask the filmmaker and author about this when we spoke.

What's The Big Change Made In The Woman In Cabin 10 Film, And What Did The Director Say About It?

The premise of The Woman In Cabin 10 stays relatively unchanged in the movie. It still follows a journalist named Lo Blacklock (played by Keira Knightley in the movie) as she boards a luxury yacht on assignment and witnesses the woman in the cabin next to her being thrown overboard. However, when she reports the incident, it’s revealed to her no one was ever staying in that cabin, and the entire crew is accounted for. This leads to a thrilling mystery Lo must solve on her own in order to prove herself right.

In the book, the story is told from a first-person perspective, with Lo being sleep deprived due to a recent break-in in her own home, her history of mental health struggles and a recent kerfuffle in her relationship. With that, there’s perhaps some evidence for the reader to parse through in regard to whether Lo is a reliable narrator or not. However, the movie doesn’t really have any of these details. Simon Stone, who co-wrote the script and helmed the film, spoke to CinemaBlend about the changes, saying:

I think that I wasn't interested that the genre is replete with examples of unreliable narrators or unreliable protagonists in this particular case. And, I feel as if that wasn't the kind of particular niche that we could fulfill with this. I think there was an opportunity to make it about conspiracy, about the outrage of fighting against corruption.

Stone also added in our interview that he thinks Lo is a believable character regardless of her mental state. As he continued, the changes were made in order to highlight the strengths of the story and avoid thriller tropes. In his words:

I think it's less interesting, because the audience has already experienced a lot of gaslighting stories. It's less interesting for them to find out whether she's mad or not. I think it's much more interesting given that the coup of the twist is such that it really is impressive when you find out what actually happened. That it's actually much more fun to get the audience to go, 'I need to find out what happens so that I can agree with her because she seems incredibly convincing'… It makes it a much more heroic story.

The movie also makes Lo a much more active character throughout, who is more central to the answer of the mystery than the novel originally made her. Hey, the book was made in 2016 and, as we’ll discuss with my chat with the book’s author, a book and movie are different mediums to consider.

What Ruth Ware Thinks About The Woman In Cabin 10 Change

In a separate interview, I asked the best-selling author behind the book, Ruth Ware, about the change to Lo’s characterization. She provided some very intriguing thoughts to CinemaBlend:

I mean, obviously, as a writer, you've got a very different sort of toolkit to work with in terms of Cabin 10 is a first person book. So we're entirely inside Lo's perspective. The whole time we see the world through her eyes, we only know what she perceives and tells us.

It’s perhaps more attractive as a writer to create a character in a thriller with some obvious blindspots to entertain and challenge the reader further. But, when it comes to her thoughts on the changes, Ware feels they align with her original intentions with the book anyway. She said this:

[The movie is ] true to the sort of spirit of the book, which is that Lo is actually very reliable, but also from the point of view of craft, a film is an external thing. We, the viewer, know what we have seen. We are not seeing it through Lo's perspective the way we are in the book. So there, in a way, it's not as easy to portray an unreliable narrator in film, full stop.

Ware said she “never saw her as an unreliable narrator”, just someone who other characters in the story saw that way. Ware also shared more thoughts:

I slightly quibble with people who describe Lo as an unreliable narrator. I give people in the book lots of reasons to doubt her, but fundamentally what I was trying to get at was to say to the reader, ‘Why are you doubting this woman's word when what she tells you is the truth?’

Well, there you have it! It's always interesting to hear the director or screenwriter of a book adaptation to explain their rationale for changes made to the story. Of course, it's also great to hear what the author of the source material thinks about alterations as well. In this case, it seems Simon Stone's adjustments made sense in the eyes of Ruth Ware, which is quite cool, given such changes could've been risky.

Check out The Woman in Cabin 10 for yourself on Netflix now. Also, read up on what it was like for Keira Knightley and the cast to film the movie on a yacht. And, of course, be sure to stay remain in the know when it comes to 2025 Netflix movies that are on the way.

Sarah El-Mahmoud
Staff Writer

Sarah El-Mahmoud has been with CinemaBlend since 2018 after graduating from Cal State Fullerton with a degree in Journalism. In college, she was the Managing Editor of the award-winning college paper, The Daily Titan, where she specialized in writing/editing long-form features, profiles and arts & entertainment coverage, including her first run-in with movie reporting, with a phone interview with Guillermo del Toro for Best Picture winner, The Shape of Water. Now she's into covering YA television and movies, and plenty of horror. Word webslinger. All her writing should be read in Sarah Connor’s Terminator 2 voice over.

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