An episode of sparrows

Someone has dug up the private garden in the square and taken buckets of dirt, and Miss Angela Chesney of the Garden Committee is sure that a gang of boys from run-down Catford Street must be to blame. But Angela's sister Olivia isn't so sure. Olivia wonders why the neighborhood children--the "sparrows" she sometimes watches from the window of her house--have to be locked out of the garden.