I'm about halfway through my novel and I've reached a major turning point in the plot. It's a urban/modern fantasy. Half of the book is about my MC, a detective, gathering information on werewolves, vampires, and other beasties, trying to figure out where they came from and why they're out to kill us all. The second half of the book takes a major turn; the leader of these creatures returns (he was sealed away in an alternate dimension 1,000 years ago, along with all kinds of other "things") and declares war against all mankind. There's some foreshadowing and certain characters clue my MC (and the reader) in on what is about to happen, but I feel like the transition is kinda rough. It's peace one day and havoc the next, if you know what I mean. I suppose what I'm asking is, have any of you read a book like this and, if so, what did you think of it as a whole? I'm worried that the second half may disappoint readers who came to like the slow, technical approach of the first half. Or perhaps readers who enjoy war scenes and epic battles won't read through to the second half. There's a good mix of both throughout the novel, but the shift in emphasis is so sudden it troubles me.
One book i can think of off the top of my head that is a bit like this is the 3rd one of the Bartimeous Trilogy. For the 1st half, it is pretty similar to the 2 that come before it, with the main characters doing day to day things in the running of the magical empire and trying to uncover a conspiracy. Then in the second half Spoiler The people behind the conspiracy put their plan into effect and overthrow the government. However, to cut a long story short, they try to become more powerful using demons and as you might expect, the demons trick them and end up in control. The last 3rd of the book is about the demons literally taking over the city, and the main characters coming up with a plan to defeat them. I enjoyed the book overall, even though there was a major shift halfway through. The previous 2 books and the 1st half of this one, while they still involved people trying to take over the government, were usually all about picking up clues as to who is behind it and what their plan is. The change between this and Spoiler fighting an army of demons is quite drastic, but the writing and characters were good throughout, and i enjoy both detective type stuff and epic battles, so it was fine for me. As long as you at least hint that it could go to the type of scale it does (which it sounds like you have), it should be fine. If i was reading something about a detective trying to prove that a man killed his wife, and then suddenly the man holds the city ransom with an atomic bomb, it might put me off a bit. However if the man was a high ranking government official, and the detective suspected his wife was murdered because she was going to tell everyone about a conspiracy the man was involved in, then it could make the transition.
There are several books I’ve read where character/s are thrust into action from one moment to the next. The difference is, in a complex plot the transition cues can be masked or disappear entirely. As an example, in The Hatchet, the character’s plane crashes. Even though the action begins suddenly, the change is easy to understand. When citing alternate universes and coolness like that, its important to not loose the link from peacetime to chaos.
It might help to have a minor major conflict before all hell breaks loss. The kind of event that catches everyone attention and is kind of obvious what it really is but no one wants to admit it. With something somewhat violent and major having already happen, the all out declaration of war will be a little less surprising, but ultimately somewhat smoother.
Rough transistions? LOTR: Book 1; happy halfling -> 3 pages later -> not so happy halfling aparantly holding an item that can destroy the world (Is it secret, is it safe). Wheel of Time: I'm a happy farmsboy -> 3 pages later -> I'm a terrified farmsboy being hunted while my dad just got butchered. I could go on. The trick, like you pointed out, is foreshadowing. Although I can't really point out how you should do this; how does this leader return? Did any of the bad people mention him? If he isn't mentioned before, people will react like "Who the hell is this, where did he come from?". Good transistions; examples above, foreshadowing. Bad transitions; Pirates of the Carribean... ("Uhm... and now... Kraken appears. And he... kills... no, no, eats, Jack Sparrow... and then Kraken is dead... and there are ninja's... and pirates?")
Well, I'd figure that in a situation like you've presented, a quick transition is understandable. However, it sounds to me that perhaps you didn't do enough foreshadowing? If you think it seems to come out of nowhere, what sort of change needs to be done to the foreshadowing?
I always love stories like this and I like the fact that things turn on a dime. After all one minute life IS breezy, the next minute it's falling down around your ears. Foreshadowing is important but so long as everything is properly introduced, so it's not fighting against the surroundings, you'll be just fine. Sounds like a fun read, hope it all goes well.