Spring 1917: the privileged world of Sorn Castle is upside down, its stately rooms full of amputees from the Western Front. While the local aristocracy makes a first attempt at nursing, a romance blossoms.

'Please don't slam your door - we have a delicate child', but when the baby cries, Deb ignores it. There is a secret which is destroying Deb's marriage to Greg. Only she can save it - only Deb can unlock The Dark Room.