The boys embark on a mission to relieve the starvation of a neighbouring village, occupied by the Chipewyans, but due to a series of unfortunate events become trapped above the tree line in Canada's northern Barren Lands during winter.

Jamie's parents died in a car accident in Toronto in 1931, and four years later he is under the care of his trapper uncle, Angus Macnair, who lives in Manitoba.

Angus has supported Jamie's Saint George's boarding-school fees for a long time, but no longer does now that the fur trade has begun to decline.

It is eventually decided that Jamie has to stay in camp with Awasin because Angus's canoe could not hold three people as well as all of the gear.

Soon, they go up to the North farther, but they do not find any 'deer' (in the book, deer means barrenland caribou); so Denikazi orders Jamie and Awasin to stay with two young Chipewyans at a certain point until they come back.

A problem occurs, for one of Denikazi's men sees what he believes is an Inuk and they all flee quietly back.

Jamie and Awasin are then forced to overcome a series of obstacles including finding shelter and food and to wait until the summer when they can make the trek back to their home camp with the best chance of survival.

They engage in a massive caribou hunt, and are able to build a log cabin and make a comfortable home for themselves.