The park have said there will be a story, to some degree. I imagine that will mostly be communicated by videos / marketed. In terms of at-the-ride theming, I doubt it will be much beyond landscaping, stylising buildings, logos/images and not much else. The plans don't indicate any theming.
I don't think the ride needs much theming anyway. As said above, the height will do the talking. The location around the lake will add to the vibe. A good, long soundtrack will help create an atmosphere. Onboard audio hasn't been confirmed or denied yet, but could still happen, and would add a lot. I expect there could be actors during the first few days/weeks around the plaza, just to add a bit more to the area.
In other news, here's a look at what's been built so far in terms of supports/track:
If absolutely everything goes to plan, then - according to the original scheme of implementation in the plans - the ride could be ready by mid-March. Obviously there's a lot of variables there, but I think there's a good chance the ride could open at the start of season.