I and others have discussed the possibility that this would be a long book because of the large number of characters, complications and potential conflicts that might play a role or arise during this novel. We already known about what Thomas told Harry in chapter one. If you don't know, I'll just say it means Lara will most likely be involved, plus I imagine she will play a part in the talks between the Fomor, White Council and anyone else who shows up. Marcone will almost certainly be the host of the talks, plus he has had some conflict with the Fomor. We know from the end of Skin Game that the relationship between the crime lord and Harry is quit frosty, so there's potential conflict in that area. We know the White Council; or at least a couple of important members from it, will play a role in the novel. We can only speculate about how that might play out, but it's almost certain to cause trouble for Harry. From the photo from the book's trailer that Priscellie posted on Jim's website, it looks like someone from Summer is there and that means Winter will be there too. So as a guess that means Molly, Sarissa and their retinues will make an appearance; and isn't it about time for Michael and Charity Carpenter to find out about Molly's new gig? There is also the possibility Ivy will be on hand to mediate the talks and that would mean Kincaid will be there too. Now add in new characters from other supernatural nations, the Fomor themselves and one or two wildcards; like Cowl or Mavra, lurking in the background and perhaps eventually making an appearance, and you've got quit a stew about to come to a boil and start splattering the stove.
I'm sure some of these potential conflicts will be more for show and won't get resolved until a later novel. For example, perhaps no matter how tense the situation between Marcone and Harry might seem to be getting, in the end it might be something that gets put on a back burner until another time. That's not a prediction, just one way Jim may work through some of these complications. Even so, there should be a lot of crazy and fun situations for Harry to deal with, and a lot of reading for us to savor. There's no way this was going to be short novel.