Ruth Ware’s wildly popular novel is an exercise in internal anxiety reminiscent of Edgar Allan Poe – just much longer. The first-person narrator, Laura (“Lo”) Blacklock, is a journalist for a British travel magazine. She scores a plush assignment of sailing on the maiden voyage of a small luxury cruise ship/yacht owned by a rich industrialist who wants to market it to the ultra-exclusive luxury market. On board are an assortment of potential investors and media representatives, including Lo’s former lover, and the ship’s owner and his wife. Lo, however, has trouble relaxing and enjoying the trip because she is a basket of nerves. She suffers from manic depression, and just before the trip her apartment is burglarized, while she was home, leaving her slightly injured and extremely jumpy. She also has an alcohol problem, which doesn’t mix well with her anti-depressant drugs, and since the robbery she hasn’t slept much. So, when things turn weird, Lo is already on the edge of madness and doesn’t need much to push her over the edge.

The core of the novel is Lo’s internal struggle to maintain emotional control. The fact that she’s paranoid doesn’t mean that people aren’t really out to get her. The author’s extensive use of inside-her-head descriptions works with the first person present narrative, although I’m not a huge fan of the reader’s information coming from the protagonist’s thoughts rather than from events that the other characters in the story also experience. But, give Ms. Ware credit, the conceit works pretty well and generates a high amount of tension.

The story itself is an intricate and complex whodonit in a classic “locked room” setting. Lo meets a young woman occupying the cabin next to hers – cabin 10 – and borrows a mascara from her. That night, Lo hears a cry and a spash. She rushes to her balcony and thinks she sees a body sinking into the dark water of the North Sea. She thinks somebody, probably the young woman she met in that cabin, has been murdered. When she tries to alert the ship’s security chief, he doubts her story because (1) Cabin 10 is not occupied, and when they check, it’s totally vacant; (2) Lo had been drinking heavily earlier in the evening; and (3) every member of the ship’s crew and all passengers are present and accounted for. The rest of the book is all about Lo’s efforts to figure out what really happened, while somebody seems to be thwarting her efforts. Did she maybe imagine the whole thing? Or, is there a killer on the ship?

There are a few flaws in the story, and a few loose ends that don’t ever mesh. The set-up takes a long time before Lo even gets on the ship, and much of it is not really necessary. There are some major clues that end up hanging without resolution, and it’s never entirely clear why Lo cares so much about the potential murder that she’s willing to abandon her writing assignment and make it her personal quest. At times the prose is over-written with excessive adjectives and adverbs as well as unnecessarily obscure language. The ending is both convoluted and also leaves some major issues hanging. I was not a fan of the end-of-section reprinted emails and social media posts that were mostly red-herrings and intentional false leads and distractions. They were not really necessary and did not add to the suspense. But, even with these flaws, it was a compelling story where the tension and the intricate plot keeps you reading.

I understand why this novel has received such acclaim and such a following. The protagonist is very flawed and easy to relate to, and the mystery is intriguing and difficult so solve. Lo guesses the truth with the help of a convenient reveal and a couple leaps of logic, while the reader has very little chance to guess before Lo’s internal thoughts give it to us. It’s a twister, and the confined space of the ship makes everything very claustrophobic – as Lo experiences the same emotions. It’s a well-done book, but with plenty of aspects that could have been better.