Jacob is a 23-year-old veterinary student at Cornell University whose life shatters after the sudden death of his parents. Left penniless and grieving during the Great Depression, he impulsively hops a moving train and lands in the chaotic world of a traveling circus. The narrative also follows Jacob as a nonagenarian in an assisted living facility, where he struggles with the physical limitations of aging and clashes with the condescending staff while clinging to his vivid memories.

Marlena is the star equestrian performer of the Benzini Brothers circus. Disowned by her family after running away to marry August, she finds herself isolated within a volatile and controlling marriage. She possesses a natural affinity for the animals she works with and attempts to maintain peace in an incredibly unpredictable environment.

August is the head animal trainer for the Benzini Brothers circus and Marlena's husband. He oscillates wildly between charming generosity and terrifying cruelty, driven by an undiagnosed mental health condition. Tasked with managing the menagerie on a razor-thin budget, he enforces his authority through intimidation and brute force.

Uncle Al is the dictatorial ringmaster and owner of the Benzini Brothers Most Spectacular Show on Earth. He projects a jovial public persona in his scarlet coat and top hat, but this masks his predatory business practices. He builds his operation by scavenging the remnants of bankrupt competitors and rules his workers through the constant threat of tossing them from moving trains.

Walter is a clown performer who performs under the stage name "Kinko." As a little person, he faces severe discrimination and is relegated to the lowest social tiers of the traveling show despite his status as a performer. He reads classic literature to hide pornography and maintains a highly prickly, defensive exterior to survive in a hostile environment.

Camel is an older, weathered circus laborer and World War I veteran who takes pity on the newly orphaned Jacob. His body is failing from age and hard labor, making him highly vulnerable in the cutthroat circus economy where useless workers are violently discarded. He relies on toxic Prohibition-era liquor to numb his physical pain.

Rosie is a massive, highly intelligent elephant purchased in a desperate bid to save the circus from bankruptcy. Though her previous trainer claims she is stupid and requires brutal discipline, she possesses a keen understanding of her surroundings and surprisingly understands commands in Polish.

Rosemary is a 47-year-old nurse at the nursing home where the elderly Jacob resides. She stands out from the rest of the staff by treating him with genuine dignity, listening to his complaints, and offering comfort when his memory falters.

Joseph is a new resident at Jacob's assisted living facility. His boastful lie about carrying water for circus elephants deeply offends Jacob, sparking a bitter rivalry that highlights Jacob's intense protective feelings over his circus past.

Earl is a massive, intimidating circus worker who serves as Uncle Al's physical muscle. He enforces the ringmaster's brutal decrees and frequently escorts individuals to face punishment, acting as a looming threat to the lower-tier workers.

Catherine is Jacob's beautiful, upper-class college girlfriend. She represents the safe, predictable, and respectable life that Jacob is violently torn away from after the death of his parents.

Queenie is a Jack Russell terrier and Walter's fiercely loyal pet. In a harsh environment where Walter faces constant discrimination, Queenie serves as his only source of unconditional comfort and companionship.

Charlie is the manager of the modern circus that the elderly Jacob escapes the nursing home to see. He possesses a deep respect for circus history and recognizes the value of the older man's experiences.

Barbara is a sideshow performer and sex worker for the Benzini Brothers circus. Her presence highlights the exploitative and seedy underbelly of the traveling show during the Depression era, as she makes a meager living through private encounters.

Grady is a laborer on the Benzini Brothers circus train who, along with Camel, helps Jacob acclimate to the harsh reality of life on the rails.