Jack is 14 going on 15. For the past seven years, he and his younger brother and sister, and his mother and father, have lived in a remote cabin on the Athabasca River west of Edmonton. It's the late 1930s, and the river is almost as wild and untamed as it was before humans began settling along the riverbanks.
The reason for the Whyte family living there has a good deal to do with Malcolm, Jack's father, and what we would call his PTSD after serving in World War One. He has never really recovered from the trauma of his experience in the trenches, and his solution has been to sweep his family into the wilderness and remain there, living off the land. But now Jack is of an age when he figures he has had enough of this life, particularly since his father is not the most understanding of parents.
Trouble is, as Jack makes his move to leave the family by canoeing away down the Athabasca, something goes wrong on the first day and he breaks his arm, and has to stay stranded, alone, unable to make any more progress. Malcolm comes after him, and somehow father and son begin to communicate in ways they never have. All of this is played out against the backdrop of a powerful river where nature is dominant and where a family manages their lives alone in the bush, with little or no reference to the world beyond.