Senda, a Native American boy, lives with his father on the Canadian prairie near the Sierra Nevada mountains. He encounters two orphaned grizzly bear cubs, Jackie and Jill (also called Nuca), after their mother dies accidentally during a hunting incident involving his father. Senda names the cubs and forges a deep bond with them through shared play and companionship. Following the bears' loss, he persuades his father to let him adopt and care for the cubs, bringing them into their home. Senda's relationship with the bears is built on mutual trust and protection, especially shielding them from hunters who pose a threat. As Jackie and Jill mature, Senda understands they must return to the wild and guides their reintegration into the wilderness. His actions reflect both a profound empathy for wildlife and a strong sense of ecological responsibility. Senda navigates the space between human environments and wild nature, interacting with characters like Olga, a farmer's daughter, and confronting antagonistic figures such as the hunters Forrester and Bonani, who actively pursue the bears. Senda's journey concludes with him securing the bears' survival and freedom within their native ecosystem.