“The Sounding of the Call”, Buck travels with John Thornton, his friends and the sled dogs team down to the Lost Cabin, and after many days, during the summer, the have found the Lost Cabin. But, it is not a shelter, the Lost Cabin is a shallow valley, loaded with gold. "They went across divides in summer blizzards...on naked mountains... but, a shallow place in a broad valley where gold showed like yellow butter.
A few days after arriving in the valley, Buck begins to change. Buc begins to run into the woods, admiring nature and becoming more alert. "Irresistible impulses seized him... when suddenly his head would lift up and his ear cock up, intent and listening... he loved to run in the dim twilight of summer midnights."
Buck finally starts to give into the call and goes into the woods, and after wondering around, meets with a timber wolf. The wolf becomes afraid of Buck, and tries to run away from Buck, but, eventually trusts Buck. Both the wolf and Buck begin to run deeper into the woods, by the time they’re at the edge of the forest, Buck turns back to go back to John Thornton’s camp, saying goodbye to the wolf. "...till he came to an open place among the trees... a long, lean timber wolf... It was a mournful howl, and as Buck steadily on his way."
Buck wonders off back into the forest, traveling more into the forest, killing and eating off of living things, such as himself; hunting for himself. Eventually, he learns never to let prey escape. "... he wondered for a week... The blood-longing became stronger than before. He was a killer, a thing that preyed, living on things that lived...
Buck becomes alert again, walking the trail to John Thornton’s camp, which is now ransacked, the men, dogs and John Thornton himself are all killed by the Yeehats. Buck becomes angry by this and, starts killing the Yeehats. "... found Nig. He was lying on his side, dead... he found Hans, lying on his face, feathered with arrows...He sprang at the foremost man, ripping the throat."
Buck meets up with the wolf pack of the forest, reuniting with the wolf he met, before leaving him to go back to John Thornton’s camp. The alpha (leader of the pack) comes and greets Buck, howling towards the moon. Quickly, the other wolves and Buck join in, Buck welcomed into the pack and running into the forest with the pack. "... Buck recognized the wild brother... Where upon the old wolf ... and broke out the long wolf howl... He sat down and howled... Buck ran with them, side by side with he wild brother beside him."