Sinner is an emotional read (like all of Stiefvater's books). It takes your feelings and stomps on them, revelling in your tears and heartbreak.
Ok. It's not that extreme. But it is rather intense.
Sinner is a raw, unapologetic look at the darkest parts of the human spirit. It's not a hopeful story of love and loss like Sam and Grace's story. Isabel and Cole bare the darkest secrets of humanity's soul. Surprisingly, it's very light on the supernatural themes. The other books focussed much more on the 'werewolf' side of things, but Sinner is more a story of a...