Hemlock Grove Season 2 will go beyond the Brian McGreevy novel on which it is based, according to executive producer Charles Eglee in an interview with Collider:
I haven’t read Brian’s book. I look forward to it at some point, but after I finish working on the show. When I was running Dexter I came onto the show at a point when they had exhausted the underlying material. They had finished the first book. And I remember somebody, one of the higher-ups from somewhere, saying “Oh my God! What are we going to do? We’re out of story!” And it was just the most perplexing thing in the world for me to hear that. We’ll do what every storyteller does, we’ll make shit up! The table was set last year by the novel and the show and we’ve taken that into the future.
Eglee describes Season 2 as having “a beginning, middle and end,” picking up with a three month time-jump:
We’re suggesting that there’s been a three month gap between the end of last season and this season. But in scrutinizing, we have someone in our office who is dedicated to understanding the mythology of last season to the degree that the mythology is decipherable, because it got a little dense and sometimes contradictory. Last season actually there was a big time jump, I believe in the last episode. There was something like seven months between when Shelley was shot and Letha was born. We kind of had to account for that in our storytelling.
Hemlock Grove Season 2 drops July 11 on Netflix.