This gripping novel for young readers begins in 1805, when fifteen-year-old Duncan Scott and his sister Libby lose their parents in a Glasgow cotton mill fire. Their tragedy is compounded when, through one reckless act of grief, the Scott children become fugitives as well as orphans, and must flee Scotland. Across the border in England, Duncan and Libby are betrayed by their travelling companion. In a desperate attempt to save Duncan from the gallows, Libby sacrifices her freedom for her brother's - a selfless act of courage on the Liverpool docks that sends her to prison and propels Duncan over the storm-swept waters of the Atlantic to Canada. After a year in Montreal, Duncan is enlisted to travel by canoe across the continent to New Caledonia, carrying secret orders for the trader, Simon Fraser. Before he can go home and find Libby, Duncan must join Fraser on a dangerous voyage of discovery to the Pacific Ocean, a journey down what Fraser assumes is the Columbia River but which turns out to be what later will be called the Fraser. Along the way, Duncan faces death, danger and treason, and must somehow find the courage to save his companions, the expedition, and himself.