The visitors from downriver had strange pale skin and blue eyes, but they left a deadly sickness of red spots and fever.

Thirteen-year-old Millie and her younger sister Maura were the only survivors.

As the first snowflakes fell the dogs were turning wild, and it was clear that the two girls must leave to find a new home.

They loaded up a raft to take them away, and so began an epic journey through the harsh snowy landscape.

This is an extraordinary story of courage, commitment and survival.