Returning to Rome after three years in the field, General Marcus Vinicius (Robert Taylor) meets Lygia (Deborah Kerr) and falls in love with her, though as a Christian, she wants nothing to do with a warrior. Though she grew up Roman, the adopted daughter of a retired General, Lygia is technically a hostage of Rome. Marcus gets Emperor Nero (Sir Peter Ustinov) to give her to him for services rendered, but finds himself succumbing gradually to her Christian faith.