A wolf-dog in the Yukon is brutalized by nature and by men until finally finding kindness and domestication in California. London wrote this as a companion to The Call of the Wild, reversing its trajectory: instead of a tame dog becoming wild, a wild creature becomes tame. The violence is unflinching, the nature indifferent, the survival desperate. London knew this territory from his own time in the Klondike. The novel asks whether love can overcome brutality, whether the wild can be civilized. The ending offers hope that feels earned because of the suffering that precedes it.