It's 1900 and Skerry, a small Scottish fishing village, is destined for an unyielding winter. During a storm, a young boy washes up on the shore. He bears an uncanny resemblance to teacher Dorothy's son, lost to the sea at the same age many years before, his body never found.

The village is soon snowed in, and Dorothy agrees to look after the child until they can uncover the mystery of his origins. But over time, the lines between reality and desperate hope start to blur as the boy reminds Dorothy more and more of her own lost child.

The boy's arrival also finally forces Dorothy to face the truth about her brief but passionate love affair with Joseph, the fisherman who found the boy on the shore and who has been the subject of whispers connecting him to the drowning of Dorothy's son years earlier.

As the past rises to meet the present, long-buried secrets are unearthed within this tight-knit community, and the child's arrival becomes a catalyst for something far greater than any of them could imagine.