Countess's Calamity — Sally Gardner

This is the story of five little dolls that are left in a box, in a park, under a chair. Nobodyknows why they were left here, but one day, a couple of retired mice discover them, the box is blocking their doorway. Soon, the dolls and the mice become friends...except for the Countess, who's a little too hoity-toity to befriend any mice. But she doesn't have any choice and soon the dolls learn to stay away from the "legs" (humans), forage for food, and have a great deal of fun with the mice. The Countess's Calamity is the first in a series of four books about these lost dolls called Tales from the Box.