Harrison William Shepherd grows up between Mexico and the United States, never fully belonging to either world. As a young man in Mexico, he becomes involved with prominent figures such as artists Diego Rivera and Frida Kahlo, and later finds himself working as a secretary to the exiled Russian revolutionary Leon Trotsky. Moving through these charged historical and cultural environments, Shepherd observes events from the margins, recording his experiences in journals that capture both public history and private reflection.

After returning to the United States, he achieves success as a writer, but his ambiguous past and foreign ties soon draw suspicion during a period of political paranoia. As scrutiny intensifies, the gap between his public persona and private life widens, and he must confront the consequences of being caught between identities, nations, and expectations.

Spanning decades and continents, The Lacuna explores themes of exile, memory, and the power of narrative. It is a novel about the spaces between things—between cultures, truths, and versions of the self—where meaning is often shaped as much by what is missing as by what is present.