The crying persisted. The door of the ligthhouse clanged in the distance, and Tom's tall frame appeared on the gallery as he scanned the island with the binoculars. 'Izzy!' he yelled, 'a boat!' He vanished and re-emerged at ground level. 'It's a boat all right,' Tom declared. 'And -- oh cripes! There's a bloke, but -- 'The figure was motionless, yet the cries still rang out. He hoisted out a woollen bundle: a woman's soft lavender cardigan wrapped around a tiny, screaming infant. Tom Sherbourne, released from the horrors of the First World War, is now a lighthouse keeper, cocooned on a remote island with his young wife Izzy, who is content in everything but her failure to have a child. One April morning, a boat washes ashore carrying a dead man - and a crying baby.

Safe from the real world, Tom and Izzy break the rules and follow their hearts. It is a decision with devastating consequences.