Tom is a World War I veteran who maintains a lighthouse off the shore of Australia with his wife Isabel, a woman desperate to have a baby. Her prayers are answered when an infant washes up on shore in a rowboat. Tom thinks they should notify the authorities but ultimately gives in to Isabel's wish to keep the girl. Fate strikes again when the couple meet the child's biological mother on the mainland. Now, Tom and Isabel must make a decision that will forever affect the lives of four people.