Beginning in ancient Spain, where Hannibal's father had carved out a Carthaginian empire, the novel traces the origins of the war, the opening moves, and Hannibal's inspired choice to attack Rome via a land route most believed impossible. In graphic, panoramic prose, Durham describes the battles, including the icy slaughter of the Trebia; the mist-shrouded battle along Lake Trasimene; the battle of Cannae, in which Hannibal's outnumbered force surrounded and decimated seventy thousand Romans in a single afternoon; and Zama, the hard slog that proved to be the decisive contest.

Along the way we meet a variety of major historical figures on both sides of the conflict, as well as characters representing the vast array of other ethnicities who played a part in the war: Iberians and Gauls, Numidians and Libyans, Macedonians and Moors. Hannibal's family is brought to life: his wife, mother, sisters, and young son, as is Publius Scipio, the young Roman who was the only match for Hannibal's genius on the field of battle — and who eventually defeated him.