A house has been split up into flats, and Coraline has moved into one with her parents. They have eccentric neighbors -- two actresses who read tea leaves, and a man who claims to be teaching a mouse circus -- but there's very little for Coraline to do. She explores the garden and (when it rains) the house, which is where she finds the door that opens to nothing but a brick wall.
Except that one day, she finds it doesn't open to the brick wall but an image of the house. An eerie image, where her mother and father have buttons for eyes.
And the plot then starts to twist and convolute and lead you down some interesting byways before it resolves. Knowing some British folklore may lead you to see some interesting parallels with the other house, as well.
An eerie and enchanting tale. And the cat's cool.