Lucy Pevensie unwittingly finds Narnia in a magic wardrobe. This is a project that I have proposed on Cuusoo. Three movies have been released, one is in the works, and three more still remain. I would love to have a whole world of Narnia LEGO sets. To that end, here are some of my ideas.
I like the idea of a two-sided set. Going from one side to the other requires some sort of magic. In this case a wardrobe takes one into Narnia where we meet Mr. Tumnus.
Similarly, young Digory Kirke and Polly Plummer find themselves at the mercy of Uncle Andrew. He craftily sends Polly into the Wood between the Worlds and Digory is forced to go after her.
From there they explore Charn and accidentally bring back Jadis. Evil then enters Narnia.