Charley, Charlotte and the Golden Canary

A boy and a girl are friends, and then the girl moves into a tall building which is so tall her mother never lets her out to play anymore, and the boy doesn't know where she moved to because all the buildings are alike, and so they're sad. He buys a canary, and accidentally lets the canary out, and it flies away and he chases it, and it flies to the girl's house and she sees him and then they're friends again. The end.

It takes a long time to tell this story, and there's not much to it. Pretty boring book that relies on contrived coincidences.