A story of the Second Punic Wars, beginning with Scipio's futile pleas to the Roman Senate to build an army to battle Hannibal, that climaxes with the battle of Zama.

Lieutenant Mario Ludovici, an army officer, gets himself transferred to a Libyan post when his romance with society girl Cristiana goes on the rocks. Ludovici is looked upon as a weakling by Captain Santelia, the hard-boiled commander of the troops, but after a bitter campaign against a rebel tribe Ludovici proves his true worth and returns as commander when Santelia is mortally wounded. Cristiana arrives and tries to entice him to return to Rome, but he decides to stay in Africa with the army.

A veteran of the African War, along with two young men, one of whom is newly married, are called to arms to defend their homeland's borders. They will be protagonists of dramatic events involving assaults, retreats, and life in the trenches. The old veteran of the African War will ultimately perish as a hero, while the other two will return to their homes after the victorious battle to recount the dramatic events they experienced.