Marcellus is the son of a prominent Roman senator who shows up at an outdoor slave auction. At the auction Marcellus renews an old childhood friendship with a young woman named Diana. Diana remembers that Marcellus promised to marry her when they both grew up. Marcellus grew up to be a ladies man, but he does care for Diana. However, Diana was promised to Caligula.
Diana, Caligula (played by Jay Robinson) and Marcellus Gallio.
Demetrius is very affected by the Nazarene. He senses that there is something special about Jesus as he observed him prior to being betrayed by Judas. Demetrius also witnessed Jesus carrying the cross to his own crucifixion and tries to help him when Roman soldiers start whipping him for falling.
Demetrius is in agony as he stands in front of the cross that Jesus is hanging from and he is also holding the robe that Jesus was wearing. Demetrius knows without a doubt that Jesus is the Son of God.
After the body of Jesus expires Marcellus touches the robe and immediately is affected mentally by it. Marcellus feels that he is now losing his mind. As time goes by he learns more about Jesus from people who were healed by Him and from one of the disciples. Demetrius realizes that he took part in a great injustice.
Marcellus becomes a Christian and warns Caligula that Rome must choose the way of justice and charity if it is to survive. Caligula is incensed and sentences Marcellus to death.
Diana rejects Caligula and chooses to die with Marcellus as a Christian.
Marcellus and Diana march off to serve the Kingdom of God and to their earthly end.