Dina mentioned in a post that she missed Harry being a PI. That got me thinking, when was the last time that Harry; as his primary assignment or duty, had to unravel a mystery? The answer is in Turn Coat. Harry had to find the real traitor within the White Council.
Since that novel there have been occasions when Harry has had to do some detective work; like finding out where the Red Court was holding their big shindig in Changes, so Harry could rescue his daughter, but mostly Changes was about Harry rescuing his daughter and killing anyone who got in the way. I'll bullet point the rest of the novels since then.
Ghost Story: Harry is supposed to find out who killed him, but he doesn't solve anything. Molly gives him the answer.
Cold Days: It's not a mystery story. Mab gives Harry a job. Harry wonders if Mab has lost her mind, so there is some mystery there. Eventually the Mothers clue Harry in, but Maeve stays pretty much one step ahead of Harry for the entire novel. It's her insanity that allows Murphy to kill the Winter Lady for Harry.
Skin Game: Again, it's not a mystery story. And again, there is the mystery element of what does Nicodemus want to steal and why does he want it. However, Harry doesn't do any investigation; in fact, Nicodemus openly told everyone one of the items that he wanted to grab and we never do learn what his plans with it were. Don't get me wrong, I like Skin Game, but there isn't any PI investigation going on in it.
Peace Talks / Battle Ground: I was really hoping Peace Talks would feature the murder of one of the delegates during the talks that Harry would have to solve. Of course, a murder did take place before the talks, but Harry didn't really do anything to figure out what actually happened. Unless you count Harry saying to himself, "What was Thomas trying to say to me?"
I doubt Twelve Months will feature a major mystery for Harry to unravel. Of course, I could be wrong, but at present my guess is while there might be some mystery element within the novel that Harry will have to unravel, it will be part of the larger story, not the main challenge of the novel.
Harry is no longer an ordinary wizard PI. He's moving on a much wider playing field in company or close proximity of some of the heavyweights of the supernatural world. His powers and responsibilities have grown. Harry is learning to play games of protocol and to a degree he is becoming a politician now. Not an elected politician, Harry is part courtier; when he is around Mab (Not that he likes it, he just doesn't have a choice.) and is becoming a supernatural political power within Chicago as its defender, the Wizard of Chicago.
This is all well and good, but I wonder if Harry will ever get to use his detective skills again to solve the major mystery of a story. Not just a B plot or side quest within a novel, but the main dish, the meat and potatoes of a novel. I'd like to see that happen again. What do you think?