It is 1932. Polly and her older sister, Maud, travel by train and boat from Winnipeg to an island between Vancouver and Victoria. Polly will live with their grandmother, the sisters' new guardian, and attend the small school on the island, while Maud will go to boarding school in Victoria.

Their extended family welcomes the girls warmly. New-school jitters give way to new friendships and even a new puppy, and slowly Polly feels that she is becoming part of a larger family she never knew until now.

But Polly and Maud have a dramatic secret, and they have promised each other never to tell anyone. A surprise arrival on the island, however, threatens Polly's newfound happiness and tests the bonds of family love. Can Polly keep the secret and her new life on the island?