Billy is a determined young boy living in Saskatoon, Saskatchewan, who possesses a deep love for the natural world. He maintains a massive collection of unconventional pets, ranging from thirty gophers to garter snakes, which he keeps around his home. He approaches his goal of adopting a pet owl with intense focus, believing that any obstacle can be overcome with enough effort. His deep knowledge of local wildlife allows him to care for the vulnerable animals he rescues.

Wol is a large, mostly white great horned owl who becomes Billy's first owl companion. Despite losing his family at a very young age, he possesses a bold and highly intelligent personality. He refuses to act like a typical bird, preferring to walk instead of fly and actively seeking out the company of humans. He quickly establishes himself as a dominant presence in the household and the neighborhood.

Weeps is a mottled brown great horned owl whom Billy rescues from local bullies. Having been separated from his mother prematurely and severely traumatized, Weeps is deeply timid and dependent on others for safety. He avoids conflict entirely and refuses to fly, preferring to remain on the ground or be carried on Billy's shoulders.

Bruce is Billy's faithful sidekick and closest friend in Saskatoon. He supports Billy in all his outdoor endeavors and shares his love for wild animals and prairie adventures. He views the rescued owls as a shared responsibility, eagerly helping to feed them and build their enclosures to keep them safe from neighborhood bullies.

Murray is another of Billy's close friends who shares the boys' passion for the outdoors. He frequently participates in their local adventures, helping to rescue Wol from the storm wreckage and later assisting with the construction of a secret cave on the riverbanks.

Billy's father is a supportive and practical parent who tolerates his son's sprawling menagerie of animals. Though initially reluctant to add an owl to the household, he ultimately helps Billy build special enclosures and actively defends the pets when they cause disruptions. He occasionally displays a quick temper, particularly when wild animals inconvenience him.

Billy's mother manages a busy household constantly invaded by her son's wild pets. She prefers to keep the wilder animals out of her clean living spaces, though she gradually learns to adapt to the chaos the owls bring to her daily routine.

Mutt is the family's old dog, regarded by Billy as a true family member rather than just another pet. He possesses distinct preferences regarding the other animals in the household, actively avoiding Wol's relentless practical jokes while enjoying peaceful snuggles with the much more timid Weeps.

Mr. Miller is Billy's school teacher and an amateur nature photographer. He attempts to build a photography blind to observe the owl nest but quickly abandons the effort after being fiercely attacked by a protective mother owl.

Offy is the family's maid. She is easily frightened and fundamentally unequipped to handle a household that occasionally features free-roaming wildlife in its hallways.

Georgie is an older boy from the town of Saskatoon. He exhibits casual cruelty toward animals, trapping and abusing the traumatized Weeps until Billy trades a scout knife to secure the bird's freedom.