This is a very strange book that exists.
The writing style was off-putting for me. It was written in a conversational way, where the POV character often asks you questions about her thoughts (like, "But, hey, wouldn't you do the same?") and ends chapters with awkward foreshadowings along the lines of "But, boy am I glad I interviewed that person because it ended up telling me a lot!"
The mystery was pretty easy to figure out, both the "why" and the "who." However, I admit that the copious Milwaukee and Wisco references were kind of fun to read. (Green Bay gets a shout out! Well, the casino does, anyway.) Although, Barrett has a habit of explaining EVERY road that characters take to arrive places.
Also, it was entertaining to return to a time when average people legitimately didn't understand how computers worked and phones weren't at one's immediate use.
The connection to Christmas was very thin here. It was much more a "winter" mystery with legendary large Wisco snowfalls playing a role in the story.
All in all, a strange, not particularly good, light mystery.