Suggest me a mystery or Sci-Fi book with 600-800 pages?

Going on a trip and I want to have a book that’ll last me the trip which I concluded would be the 600-800 page range. I want a Self contained story that’s not part of a series or have any sequels or anything. My favorite books right now in order is first And then there were none (so so so good, I not only loved the plot but I loved the vibe of the story and the picture it painted in my head), then the Martian (easy page turner, a couple scenes that literally gave me goosebumps, loved the plot) and lastly the Conclave (Great mystery that just made me go through the book so fast). Obviously the main theme among the three are page turner books which I know is difficult to find in a longer page book.