Thirty years have passed since Greta left Marchmont Hall, a grand and beautiful house nestled in the hills of rural Monmouthshire. But when she returns to the Hall for Christmas, at the invitation of her old friend David Marchmont, she has no recollection of her past association with it - the result of a tragic accident that has blanked out more than two decades of her life. Then, during a walk through the wintry landscape, she stumbles across a grave in the woods, and the weathered inscription on the headstone tells her that a little boy is buried here . . .