Princess for a Day — Sarah Dyer

When Clementine decides that she is going to be a princess for the whole day, her little brother, Mungo, must satisfy her every demand. From sandwiches with their crusts cut off to a special circus performance featuring all their best toys, Mungo fulfills all his sister's wants. Suddenly it becomes clear that the only thing Clementine is missing is a prince, but luckily Mungo knows just where to find one!