George and Lydia think something is wrong with the nursery. This is the exposition because it introduces what Lydia thinks of the nursery.
Lydia gets scared of the room because she thinks the lions are real. This is the rising action because shes creating a problem.
Lydia and George fight about keeping to nursery or not with Wendy and Peter. This is the climax because this is the main problem.
Gearge and Lydia decide they are going to move far away. This is the falling action because the problem is resolving.
Wendy and Peter locked the parents in the room so they can keep the nursery. This is the resolution because the problem is resolved.
The theme is take care of your kids right. Thats the theme because George and Lydia spoiled Wendy ad Peter and they didn't supervise them right so they now have locked their parents in the room and are not being disciplined.