After four harrowing years on the Western Front, Tom Sherbourne returns to Australia and takes a job as the lighthouse keeper on Janus Rock, nearly half a days journey from the Western coast. To this isolated island, where the supply boat comes once a season and shore leaves are granted every other year at best, Tom brings a young, bold and loving wife, Isabel. Years later, after two miscarriages and one still birth, the grieving Isabel hears a babys cries on the wind. A boat has washed up on shore carrying a dead man and a living baby.Tom, whose records as a lighthouse keeper are meticulous and whose moral principles have withstood a horrific war, wants to report the man and infant immediately. But Isabel has taken the tiny baby to her breast. Against Toms judgment, they claim her as their own and name her Lucy. When she is two, Tom and Isabel return to the mainland and are reminded that there are other people in the world. Their choice has devastated one of them.