This is where it all begins: Lucy's curiosity leads her to the amazing discovery that an old wardrobe, in a spare room in the house where she and her family are staying, is actually a doorway into another world. With this discovery, we can tell that we're being set up to witness all kinds of adventures and shenanigans!
Although there are other conflicts in The Lion, the Witch, and the Wardrobe, such as the arrest of Mr. Tumnus, the central issue is really the Witch's animosity toward the Pevensie children. The Witch has heard a prophecy that, when four human beings, two male and two female – "two sons of Adam and two daughters of Eve" – sit in the four thrones of Cair Paravel, her reign will end and she will be killed. In order to prevent this, she has standing orders to kidnap any humans who stray into her dominions. As soon as Lucy and her siblings enter Narnia, this peril is waiting for them.
As though an angry Witch weren't enough, Edmund makes everything worse by spying for her and telling her exactly where she can find his brother and sisters. The complication caused by Edmund's betrayal quickly becomes more important than the original conflict, the Witch's hostility.
Just when it seems as though the Witch's claim to Edmund is going to disrupt the whole four-humans-crowned-at-Cair-Paravel thing, Aslan steps in to take Edmund's place as a sacrifice. Lucy and Susan watch as Aslan is humiliated, beaten, and the White Witch raises the knife to kill him!
It seems like everything is lost: Aslan can't help them anymore, the Witch's army leaves the Stone Table to attack Peter's army at the Fords of Beruna, and Susan and Lucy feel like nothing will ever happen again. "Is this the way it's going to end?" we ask ourselves.
Whew! It's all going to be OK. Aslan is back from the dead, bigger, stronger, and better than ever. He's going to restore everyone who was turned into a statue, kill the Witch, and make sure that Good triumphs over Evil.
Everything works out. The children become kings and queens, all the baddies are vanquished, and everyone rejoices and feasts a lot. The end…or is it?