It is early in the fourth century, and Christianity has become a religion in search of a theology. Roman persecution has ended, but doctrinal debates threaten to tear the church apart as the early church fathers strive to solve a mystery inherited from their apostolic how Father and Son might both be thought of as God, and yet as distinct, without doing violence to the tenet that God is One. Enter Arius, a Libyan priest who comes to Alexandria to preach an that the Son of God is a created being of a different substance than the Father, and not fully divine. When the Archbishop condemns his teachings and banishes him from the city, his local apostacy becomes a worldwide schism, as bishops and clergy throughout the Mediterranean world take sides. Desperate to use the religion as a force for political unity, the Christian emperor Constantine calls a convention of bishops at Nicaea to resolve the dispute. As debate begins, a consensus answer seems out of reach until a young Alexandrian deacon presses a solution that will forever shape orthodoxy in a different direction.