This is psychological thriller along the lines of Girl on a Train and the like.  Some gaslighting and some maybe-not-so-reliable narrator due to consumption of lots of alcohol and in the case of The Woman in Cabin 10 some sleep deprivation and prescription drugs as well, are all part of the plot.  Laura, who refers to herself as Lo, has an assignment to go on a high end exclusive cruise ship and network and report on it for her employer.  She meets another passenger, who seems to inexplicably disappear during the night.  Lo is convinced she has been murdered and dumped overboard and proceeds to investigate.

The story is told by Lo in first person and also in emails from Lo’s friends and family as she fails to report in from her assignment and later in news reports about the cruise.  Very fast paced read, the story just flies by.  There is no lagging or unnecessary detail here.  The misdirection is a little heavy-handed and I didn’t really buy into it.  I had a pretty good idea about what had happened before the reveal, nonetheless I still enjoyed the book.  This has definitely piqued my interest in  In a Dark, Dark Wood.