Aunt Dimity and the Duke (Aunt Dimity Mystery) by Nancy Atherton ISBN 13: 9780140178418

Emma Porter is forty, fat, frumpy, and a passionate amateur gardener. When her longtime lover dumps her for a younger woman, Emma escapes the cloying sympathy of family and friends by setting out on a summer-long driving tour of England's glorious gardens. A Dimity-contrived coincidence brings her to Penford Hall, a sprawling Gothic mansion in Cornwall, where she finds a duke in search of a missing lantern with extraordinary powers. Suspecting there's more than one mystery to be solved at Penford Hall, Emma accepts the duke's invitation to stay on and restore the once glorious chapel garden to its former beauty. The dark rumors surrounding a rock star and the near-death of the duke's beautiful cousin confirm Emma's suspicions, and set her--with Aunt Dimity's ghostly guidance--on the path to Penford Hall's secrets and the pleasure of unexpected love.