Then Thomas broke his leg.

Doctor Joe must needs remain at The Jug to care for him, and there seemed no hope for Jamie but a life of darkness.
But David was confident that he could take his father's place on the trails, and with some persuasion, for the need was desperate, Thomas consented that David and Andy should spend the winter in the great interior wilderness with no other companion than Indian Jake, a half-breed.
That was an experience needing the stoutest heart.

Through long dreary months they faced the sub-arctic cold and fearful blizzards that swept the wilderness, following silent trails over wide white wastes or through the depths of dark forests, and falling upon many a wild adventure that tried their mettle a hundred times.

It was a man's job, but they both made good, and that is something to be proud of--to make good at the job you tackle.
Jamie had pluck too, but pluck alone could not save his eyes.

The mist thickened more rapidly than Doctor Joe had expected it would, and there came a time when Jamie could scarcely see at all.