Harrison is an observant young boy who grows into a historical fiction author. Raised between Mexico and the United States, he frequently feels like an outsider in both countries. He is highly protective of his privacy, dedicating his time to mixing plaster for artists, cooking, and documenting his experiences in detailed journals.

Mrs. Brown is a practical and discreet widow from the Appalachian mountains of North Carolina. She longs for travel and experiences beyond her rural, religious upbringing, eventually taking a job as Harrison's secretary. She acts as a fierce protector of his work, maintaining his correspondence and carefully typing his manuscripts.

Frida is a fierce, intense Mexican painter who creates art while battling severe health issues. She shares an avant-garde home with her husband, where she hosts lively political and artistic discussions. Despite her sometimes imperious exterior, she provides vital encouragement to those around her.

Diego is a famous, physically imposing Mexican painter committed to Communist political causes. He employs Harrison to mix plaster for his grand murals. He enthusiastically hosts exiled political figures but frequently clashes with fellow artists over strict ideological differences.

Leon is an exiled Marxist Communist leader who lives under intense security measures. He works continuously on political writing and organizing his international movement while raising chickens in his yard. He views literature as an important path to freedom and actively encourages young writers.

Salomé is Harrison's mother, a Mexican woman of Spanish descent who pursues relationships with wealthy men. She struggles with alcohol use and frequently relocates, relying on her paramours for financial support while showing little active attention to her son's daily life.

Leandro is the estate's chef who shows genuine kindness to young Harrison. He teaches the boy how to cook traditional Mexican delicacies and gifts him a pair of diving goggles, providing a rare source of stability on the isolated island.

Bull's Eye is a student at a military boarding school who does odd jobs while attending classes part-time. He introduces Harrison to the political realities of the Great Depression by taking him to observe the protests happening in Washington, D.C.

Tom is an art handler who eventually transitions into the advertising industry. He develops a close connection with Harrison, sharing moments of intimacy and scenic drives before political pressures begin to complicate their bond.

Jean is a handsome Dutch secretary working for Leon Trotsky during his exile. He handles political business and correspondence, catching Harrison's profound, unspoken admiration during their time sharing a workspace.

Natalya is Leon Trotsky's wife who accompanies him into exile in Mexico. She helps manage their household and handle the intense security measures required to keep their family safe from political enemies.

Jacson is a Belgian man who embeds himself into the social circle around the Trotsky family. He constantly seeks political feedback on his writing, though his hosts find his manuscripts tedious.

Enrique is a wealthy oil industrialist who owns an isolated estate on Isla Pixol. He is financially responsible for Salomé during her time on the island but displays an abusive, controlling demeanor.

Arthur is a Jewish lawyer who represents Harrison's legal and literary interests in the United States. He provides pragmatic advice as the political climate grows increasingly hostile toward his client's work.

Alfaro is a Stalinist artist who sharply disagrees with Diego Rivera's politics. He views art and revolution through a strict ideological lens, leading to intense arguments.

Seva is Leon and Natalya Trotsky's teenage grandson. He joins their household in exile and experiences the tense, heavily guarded environment firsthand.

Alejandro is a security guard assigned to protect the exiled Trotsky household. He forms a brief, private physical connection with Harrison during his employment.

Mrs. Biddle is a landlady in Asheville, North Carolina. She manages the boarding house where both Harrison and Mrs. Violet Brown reside, strictly monitoring the reputation and behavior of her tenants.

Romulus is a young neighbor boy who assists Harrison with household chores. He forms a friendly bond with the author until neighborhood suspicions begin to interfere with their association.

Chispa is Harrison's first pet cat in North Carolina, whose Spanish name translates to "spark." The cat's name eventually draws suspicion from conservative locals who misunderstand its meaning.

Chisme is Harrison's second cat, whose name translates to "gossip." The name reflects Harrison's quiet amusement at his neighbors, though investigators deliberately misinterpret it.

César is the elderly driver for the artists. He is inherently suspicious of Harrison, fearing the quiet, observant boy might be a political spy secretly documenting their activities.

Dr. Gamio is a friend of Frida Kahlo who works as an archeologist. He shares his knowledge of ancient civilizations and mass graves, directly inspiring Harrison's future literary subjects.

Angelino is Bull's Eye's cousin and a World War I veteran demanding his military pension. He resides in a makeshift tent with his wife and infant child during the massive protests.

Melvin is an FBI agent tasked with interrogating Harrison about his suspected political affiliations. He views Harrison's mannerisms, speech, and desire for constitutional rights as distinctly un-American.

La Perla is a regular presence at the local market in Mexico City. She provides Harrison with local gossip, including blunt, humorous descriptions of famous figures like Diego Rivera.

Cienfuegos is a local regular at the bustling Coyoacán market. He befriends young Harrison when the boy frequently skips school to wander the stalls.

Sylvia is Jacson's girlfriend. She accompanies him to social gatherings, inadvertently providing him with social cover as he attempts to integrate himself into the political circle.

Jesús is a hired driver and guide in Mérida. He transports the author and his secretary to ancient ruins and local landmarks during their research trip.

Maria is the mother of Harrison's local driver, Jesús. She lives in a humble hut on the Yucatán Peninsula and spends her time collecting orchids.