A fabulous magical journey

Two young children time travel to see their family castle at various periods in English history - some in glory, some in wreckage, as their family just escaped from running a B&B. They come back to the castle seeking the hidden treasure which will let them bring it back to its old glory, thanks to the magical Mouldiwarp white mole that transforms them, along with the assistance of a witch they befriended unknowingly with a kindness.

From the author of The Railway Children.