So after a couple hours of trying to come up with an idea, I think I found one I wouldn’t normally do.

The idea is to have two worlds connected through a mysterious device. This device was then fleshed out to be a Myst-like book. The book is found by the player in the basement of a church-like building in the real world. They are then teleported into a cartoonish world where they become trapped. They must then find the book and figure out how to use it to get back to the real world.

Other then that, I really have no clue.