Was the book different from what you expected? No. Based on the book description, the story and characters were everything I expected. The author's flawless writing and polished editing was unexpected because so many books these days come with errors in them.
Was location important to the story? Not really. This was a character driven story so any fictional place with monsters in them would suit this story fine.
Was the time period important to the story? Because this was purely fictional, I don't think a time period is important to the story. Jack goes where the monsters are so this story could have been set in any timeline, and it would have worked.
Disclosure: I received a review copy of this book from the author.