30 Day Book Challenge: Day 27 - The most surprising plot twist or ending
I'm cheating a little bit because I saw the show before reading the book but if i had read the book first then Game of Thrones by George R. R. Martin would have had the most surprising plot twist/ending. The truth is I'm rarely surprised by a plot twist or mystery in books or movies, but the character death at the end of Game of Thrones shocked me to the core. I did not see it coming at all.
Honorable Mentions: A Storm of Swords George R. R. Martin and And Then There Were None by Agatha Christie