In chapter four, Buck takes the pack’s leadership and he demonstrates his capability by making the pack travel faster than the previous leader had done. This is seen when he makes the pack travel from Dawson to Skaguay in one day instead of the ten days they had taken previously. The pack is sold to a Scotsman after Perrault and Francois receives official orders directing them to transfer elsewhere. They travel back to Dawson and one of the dogs dies from fatigue and illness (London 36).
In chapter five, the dogs are sold to new masters, Hal and Charles who travel with Charles’ wife Mercedes. The inexperience of the pack’s new masters makes them starve and carry heavier loads than the ones it carried before. The pack reaches John Thornton’s camp and Thornton frees it from Hal’s mastership (London 46). In chapter six, Buck becomes friends with Thornton, defends him from his foes, and helps him win a bet (London 55). In chapter seven, Buck and Thornton travels east to find a lost gold mine. It is here that Buck first enters the woods after feeling wild yearnings. He wanders in the wilderness with wolves and one day, he come back to his master’s camp to finds it attacked by Yeehat Indians. He attacks the assailants, killing some and dispersing the rest.