Legal Question in Intellectual Property in California

The first three levels are likely to present a copyright violation. There are two ways around this: (1) change levels 1-3 to use an original story and characters, or (2) contact the copyright holder and see if you can negotiate a license or other form of written permission to use their material and ideas. I can appreciate that using existing story lines and characters could be a good way to entice users into playing your game, but it's very likely to stir up a copyright-infringement action.

You would get a precise answer if you took your work to an experienced copyright attorney to review before you contact anyone else. It may or may not be true that you need a license. Unfortunately, if you unnecessarily contact the writer of the book, that may be taken as an admission that you owe them something and could lead to further legal issues.