This particular author is not my favorite to read from. more than half of his book that are supposed to be a supernatural (aka Dean and Sam focused story so they fit with the show!) are not from the perspective of either Dean or Sam. 
He also has a heavy focus on their parents that i don’t understand, especially since he doesn’t write them in character and/or with the knowledge that is given in the show on how they did behave and parent! 

but the out of character behavior does fit with his writing style since he just doesn’t manage to write the boys well - at all. 
could some please explain to me why this guy didn’t just get one but a more than that book deal for writing published fanfiction for a show he clearly can’t write well for since he can’t get the characters right?! who made that decision?! 

I found castiel -first time he came up in the book series- to be as out of character as per usual with the author and even the distant „i don’t understand humans“ Cas didn’t behave as he was written here. 

i did like that Bobby had a bit of a larger role here and was honestly the best written out of them all. 

the plot itself was okay but wasn’t the most thrilling best plot idea and the whole three different generations of the Winchesters having to fight the thing to finally kill it was a bit much for me.

overall? 
not impressed to be honest! 

let’s how this series and the authors that also write the books for it do a better job!

if you are an extreme fan of the show and want to read everything you can, do for it. 
if you can skip books in a series do that for this one, you won’t miss much!