Deep inside the broom cupboard of Rose Cottage, two mice live in great style. Tumtum and Nutmeg lead cozy and quiet lives, secretly looking after Arthur and Lucy, the disheveled human children of the cottage, never dreaming that so many exciting adventures will soon find them. But when evil Aunt Ivy, a squeamish schoolteacher named Miss Short, and pirating pond rats threaten the safety of those they hold dear, the courageous pair will stop at nothing to save the day.
