The Retreat is owned and run by Donald and Ruth Elkins, their three daughters, and Clover, their delightfully eccentric grandmother. Charlotte is hoping for a marriage proposal, Josie, at 15, is more interested in the annual fair, while Milly, aged 10, has high hopes of going to the local grammar school. Meanwhile Clover's nightly wanderings along the seafront are a constant worry. One night a violent storm sweeps up the Channel, demolishing the sea wall and flooding The Retreat. When bones are found in the cellars it seems only a miracle can save the Elkins family from ruin.