I was intrigued by the premise of this book when I picked it up--murder on a small luxury cruise ship--and I had enjoyed Ruth Ware's 'In A Dark, Dark Wood.' Two things in its favor. Ware has discussed her unreliable narrators in a blog post for Powell's Books (http://www.powells.com/post/original-essays/the-truth-about-unreliable-narrators) so I'm not spoiling anything when I say that the protagonist, travel writer Lo Blacklock, becomes increasingly unreliable, and even unlikeable, as the book progresses, to the point that it's difficult to stay on her side in her quest to solve this mystery. Ware enjoys the unreliable narrator because "we are all the center of our own universe" and memory is fraught with errors, but in both these books her secondary characters tend to drop away as real people, in favor of the protagonists' strong and sometimes anxious personalities. This might not even be so bothersome if the plot was compelling enough, but in this case, like a locked room mystery, we need a well-rounded set of suspects to pursue with Lo; absent that, the mystery is a bit of a navel-gazing exercise. In fact the resolution comes when the perpetrator explains what happened in a moment of stress. That's that.

It's always unfair to compare, but immediately after this I picked up an old Agatha Christie--not even a good one--and read a few pages. Granted, she is the master of the locked room mystery (or any formula), but Ware's 'The Woman in Cabin 10' might have benefited from a bit of 'Murder in the Orient Express' added to it.