Aldrin is barely sixteen, yet manages on his own at a secluded compound set deep in the wilds of Idaho. For the first time, he ventures into the countryside in search of his father, who has been away without word for two years. He encounters locals scraping to survive in a society splintered by the impact of overreaching AI technology. Aldrin must navigate the violent threats of warring militia groups as he follows cryptic clues left by his father's employer, an AI developer named Acheron. As Aldrin decodes the messages, the mysteries only deepen. Suddenly, he is confronted with the truth about his father and his own origins, but most shockingly, about a plan to burden him with duties more onerous than any mortal should bear. Once a Man is a poetically-rendered, sweeping epic, featuring breath-stealing revelations, mythic battles, gender-fluid love, and critical questions about our fate as humans. At a time when we struggle with new technology that threatens to upend our careers and lives, Once a Man daringly explores both the most wondrous and most sinister prospects for AI.