It was okay! An interesting mystery. I felt like it was very complicated though, not the mystery but the story in general.  There's leviathans,  magical? ... augments?.. and so many politics that I definitely got lost a few times. I feel like this would have been better as a second book,  and the first book should have been following Din through his exams,  and building the world there before doing a very big, twisty mystery. I was overwhelmed trying to take in all the world building while also trying to keep everyone straight in this high fantasy environment. 
Maybe it just needed to be explained better?  It was a pretty good story, I enjoyed Ana but found Din pretty boring until the very end. Pretty middle of the road for me, personally!