Cedric Errol, a seven-year-old American boy, grows up in genteel poverty in New York City under the care of his widowed mother, affectionately called "Dearest." His father, James Errol—a British aristocrat disowned for marrying an American—succumbs to a heart attack, leaving them in modest circumstances. Cedric's life shifts dramatically when he becomes the sole heir to England's Earldom of Dorincourt, compelling him to relocate to his grandfather's estate.

Renowned for his cheerful optimism and kind heart, Cedric upholds sincerity and compassion amid societal expectations. He befriends classmates Eric, Mickey, and Roy, embodying a democratic ethos that challenges the rigid class hierarchies around him. His passions for baseball and the flute mirror both his lively energy and artistic inclinations.

Initially cold and resistant, Cedric's grandfather, the Earl of Dorincourt, allows Cedric's mother only a separate residence. Yet Cedric's inherent goodness and steadfast faith in the Earl's buried warmth slowly thaw his stern demeanor. By engaging tenants and championing social justice, Cedric motivates the Earl toward compassionate governance, bridging aristocratic and commoner divides.

A subplot arises when the mother of Benjamin Tipton's son fabricates a false claim to Cedric's title. New York bootblack Dick Tipton and his brother Benjamin unravel the deceit, securing Cedric's rightful position. This resolution highlights Cedric's enduring ties to America and the steadfast loyalty of his companions.

Central to Cedric's journey is his deeply devoted bond with his mother. Her teachings of empathy and humility guide him in balancing aristocratic demands with unwavering integrity. Their unity eventually prompts the Earl to reconcile with her, symbolizing familial healing and cultural harmony.

Cedric's journey intertwines innocence with moral resolve, sparking growth in others as he upholds his principles against adversity. His tale exemplifies kindness and cross-cultural empathy as forces for profound transformation.