I interrupted my reading of Ferrante's My Brilliant Friend once I read the sample of this thriller, which is set on a cruise ship over New Year's. Strange things are afoot almost immediately, and even before the ship goes dead in the water and even stranger things happen, there's a revolving cast of interesting characters with knotty pasts (and presents) that the chapters switch between.
Who doesn't love a tight quarters story? Probably there's a literary term that escapes me, but characters dealing with one another during a disaster in a small space reminds me of "bottle episodes" of television and favorite movies like Aliens. There's something about people losing their shit or revealing how base they can be with little chance of escape.
The first two-thirds of the book do that character shuffle as things go to hell (main characters include the assistant to the spiritual medium performing, a man set on exposing said medium as a fraud, the ship's doctor, a pair of suicidal and elderly women, a member of the cleaning staff, and an ex-law enforcement security guard); cruise passengers are kept in the dark about what's happening with the ship, and the crew appear barely to know themselves. To make matters even worse, there's both a serial rapist (another major character) and norovirus on board, the latter wreaking havoc throughout the story. Meanwhile, various characters are spotting mysterious strangers, and there are rumors of ghosts.
The characters and snowballing disaster story interested me, especially near the end when shit goes totally crazy. The last third I'm still working over in my mind. It consists of news articles and NSA reports on the incident and gives an idea of what happened. I won't say much more to remain spoiler free, but I felt like the story could keep going. Perhaps it will; Day Four is a sort of sequel to this author's previous book, The Three, and I wonder what additional details would be clearer if I'd read that. The end certainly made me want to go back to the beginning knowing what's happened.