Jacky is a grizzly bear cub living with his sister and mother in the Sierra Nevada mountains. His early days involve natural exploration under his mother's watchful protection until a pivotal incident: a Native American boy, Ran, discovers the orphaned cubs after Ran's father accidentally kills their mother. Ran adopts both cubs, naming the male Jacky and his sister Gill or Jill. Jacky then resides with Ran's community at the mountain's base.

A significant bond forms between Jacky and Ran through daily interactions and shared activities during their cohabitation. Jacky becomes integrated into Ran's family environment. This relationship faces disruption when deceptive individuals, Pedro and Paco, manipulate Ran into surrendering custody of the bears. As Jacky's new caretakers, they subject him to mistreatment, including forced confrontations with wild dogs for entertainment, marking a period of exploitation and hardship.

Maturing from cub to adult bear, Jacky's narrative progresses toward an inevitable transition. The story acknowledges the necessity of his return to wild habitats appropriate for his species. This developmental trajectory concludes with Jacky embracing his natural role in the ecosystem, ultimately evolving into the bear known as Monarch within his wilderness territory.

Throughout his experiences, Jacky's story intersects with human communities, depicting interactions with both settlers and Native American groups in late 19th-century California. These connections emphasize thematic elements concerning wildlife, human-animal relationships, and natural habitats.