Wealthy, married mice Tumtum and Nutmeg find adventure when they secretly try to help two human siblings who live in a tumbledown cottage with their absent-minded inventor father.

Wealthy, married mice Tumtum and Nutmeg have a series of adventures as they try to help the impoverished human children, Arthur and Lucy Mildew, to have a good Christmas, enjoy a seaside holiday, and celebrate Arthur's birthday.

Wealthy, married mice Tumtum and Nutmeg have a series of adventures as they try to help the impoverished human children, Arthur and Lucy Mildew, to have a good Christmas, enjoy a seaside holiday, and celebrate Arthur's birthday.