Keira Knightley in the Netflix mystery

In the interest of full disclosure, I like my shipboard murder mysteries with an all-star cast and at least a hint of camp. It is therefore difficult to exceed the high water level of 1978. Death on the Nilewith the delicious feast of Bette Davis and Maggie Smith trading acid-tongued barbs and Angela Lansbury in all her eccentric glory; or years 1973 The last of Sheilawritten by Anthony Perkins and Stephen Sondheim, no less, and starring the incomparable Dyan Cannon as a replacement for brash ’70s Hollywood superagent Sue Mengers. On the other hand, that of Netflix The woman from cabin 10 takes itself very seriously.

Perhaps that’s not necessarily a bad thing for readers who loved Ruth Ware’s 2016 crime novel. But Australian theater and film director Simon Stone’s gentle, glossy adaptation, co-written with Joe Shrapnel and Anna Waterhouse, is primarily a pedestrian affair that waits for the denouement to ratchet up the suspense and show some teeth.

Keira Knightley plays Laura “Lo” Blackwood, a respected London investigative journalist traumatized by the murder of a woman who agreed to speak to her for an expose on the embezzlement of an NGO. While her editor, Rowan (Gugu Mbatha-Raw, wasted in a lousy role), doubts there’s much story in it, she agrees to send Lo on the maiden voyage of the Aurora Borealis, a “big fuck-yacht” owned by Richard Bullmer (Guy Pearce).

The husband of Anne Lyngstad (Lisa Loven Kongsli), an heiress diagnosed with stage four leukemia, Richard takes the company’s well-heeled board members on a three-day cruise that ends in Norway with a fundraising gala for the cancer foundation established in Anne’s name. He wants Lo to come cover for him to help raise awareness; she hopes that this pleasant mission will restore her fragile faith in humanity.

But the tension builds as soon as she boards the mega-yacht and begins sipping champagne amid the standard – if generally thin – character introductions. And there you have it (sorry), her colleague photo-reporter Ben Morgan (David Ajala), with whom she had a romantic relationship that ended badly, will stay in the cabin right in front of hers. Clumsy.

Also on board are the doctor and longtime family associate who treats Anne, Robert Mehta (Art Malik); arrogant party boy Adam Sutherland (Daniel Ings); high-end art gallery owner Dame Heidi Heatherley (Hannah Waddingham) and her pompous husband Thomas (David Morrissey); tech titan Lars Jensen (Christopher Rygh) and Grace (Kaya Scodelario), the influencer posing as his girlfriend for optics; plus an assortment of others. Most are either composites or departures from the characters in Ware’s novel.

Instead of “the movie star, the professor, and Mary Ann” (if only), there’s Danny Tyler, recovering drug addict and former music star, played by Paul Kaye as Johnny Depp’s love child in Pirates of the Caribbean and Gary Oldman in Slow horses. Crude and unfiltered, he is allegedly a dear old pal of the suave Richard, although the connection doesn’t calculate.

At first, Heidi looks down on Lo and asks her husband, “Why is she in jeans? I feel like there was a dress code.” Lo then makes herself the target of sarcastic digs by overcompensating for her differences – she’s the Nicholas Kristof type, more comfortable with downtrodden Kurdish women – by donning a silver sequinned number for a light, casual dinner. So left-handed.

But the script has little interest in exploring the potential for accidental humor. Instead, intrigue is sown when Lo is summoned to meet Anne at her cabin the first night. Affirming her admiration for Lo’s work “giving a voice to the voiceless”, the heiress reveals that it was she who requested the journalist’s presence.

Admitting that her mind is not what it was since treatment, Anne asks Lo to revise her speech for the gala, describing her decision to leave her entire fortune to charity and put the foundation in the hands of “smarter, kinder people.” “Charity without ego,” Lo coos admiringly.

If you can’t guess what kind of dirty deeds this portends, you need to brush up on your Hercule Poirot. A key piece of casting alone is information, although the mystery is unraveled as to exactly what happened and if there was a crime. The storyline forgoes the usual pleasures of making almost everyone a suspect – even though several people may participate.

After an involuntary encounter with a furtive woman (Gitte Witt) in cabin 10, the one next to Lo’s, the journalist hears a violent fight through the walls, followed by a splash. She rushes to her balcony in time to see what appears to be a body in the water and a bloody handprint on the wall. But the ship’s rescue alert is canceled the next day when a headcount reveals no one is missing and Lo is informed that cabin 10 was never occupied.

Despite increasingly ominous warnings to back off and stop interfering in the lives of wealthy, privacy-conscious power players, Lo remains determined to uncover the truth. This arouses hostility from the other passengers, considering her to be a madwoman who imagined everything – even after her brush with death in the swimming pool.

Knightley plays it all with intensity, integrity and plenty of biting anxiety, making the film suitably absorbing as Lo is put through the gas wringer in a glamorous, claustrophobic setting. But it’s only in the final stretch, as they move closer to docking and then disembark for the gala at a picturesque coastal location, that other characters have something essential to do.

This notably includes Witt’s mysterious wife and Richard’s head of security, Sigrid (Danish actress Amanda Collin, who I spent a scene or two convinced was Sandra Hüller). The characters of Ajala and Malik also come into play more strategically, although most of the assembled group is too colorless to make them all that compelling.

Like many original streaming sources, The woman from cabin 10 will be perfectly adequate entertainment for multitasking viewers, although it’s a bit laborious, even at 90 minutes. Stone (who directed The search for Netflix) does a competent job of connecting the dots, but where is the sense of style of these rich people? Or the breathtaking decor of a million-dollar yacht that is as tasteful as can be? We’ve seen better boats and chic wardrobes on Succession.