Harrow was just as incredible as Gideon, although it does contain significantly more gore in my opinion. 
As with Gideon, in the first 1/2 of the book, you really feel like you’re trying to put together a 1,000 piece jigsaw puzzle with no reference picture. But as the pieces start to come together, it makes the whole endeavor worth it. I love these characters as if they were my own friends, and I can’t wait to see what they get up to in Nona.