In ancient times, general Hannibal (Victor Mature) and his men are crossing the Alps to invade and conquer Rome when they encounter a Roman contingent. After a fierce battle, they capture Sylvia (Rita Gam), the beautiful niece of a powerful Roman senator, and she and Hannibal begin a torrid affair. His troops, meanwhile, steadily advance on the city. Will Hannibal's war machine succeed in its siege, or will the general be too distracted by his love to fulfill his duty as a leader?