An unidentified body is discovered in New York City, with numbers and symbols are written in blood near the corpse. Gil-mo, a North Korean national who interprets the world through numbers, formulas, and mathematical theories, is arrested on the spot. Angela, a CIA operative, is assigned to gain his trust and access his unique thought-process. The enigmatic Gil-mo used to have a quiet life back in Pyongyang. But when his father, a preeminent doctor is discovered to be a secret Christian, he is subsequently incarcerated along with Gilmo, in a political prison overseen by a harsh, cruel warden. There, Gilmo meets the spirited Yeong-ae, who becomes his only friend. When Yeong--ae manages to escape, Gil-mo flees to track her down. He uses his peculiar gifts to navigate betrayal and the criminal underworld of east Asia--a world wholly alien to everything he's ever known. .