The Locked Maze is primarily a story about being small and powerless and still saving the world - not through any personal importance or great talent or anything so dramatic, but just by being the only person who could. One night two years ago, Holly didn't die. And that one event led her to save everyone else.
The Locked Maze has a strong message against religious/social/political/racial superiority - any people who believe their side has a monopoly on what is right and good and everyone else is evil and wrong; people who pursue destructive agendas with no concern for anything but their own ideals and desires.