A noble young lady named Cecilia is a very holy and devout Christian, she admires the chastity of the Virgin Mary so much that she wants to remain a virgin forever, but she falls in love with Valerian.
They get married and Cecilia warns him that an angel watches over her and will kill him if he seeks to use her sexually in a way that is unclean.
Faith is a theme that is portrayed when the characters are given the opportunity to save their lives by renouncing to their faith but don't.
Cecilia sends Valerian to get baptized with Pope Urban. When he returns he is able to see the angel and asks that his brother Tiburse gets baptized too.
A Roman prefect named Almachius finds out about the conversion of the brothers and has them executed. He arrests Cecilia and at the trial she is condemned to death.
Almachius attempts to kill her first by having her put into a tub of boiling water, then trying to have her head cut off. The executioner fails three times.
Cecilia lives for another three days with a gash in her neck before dying, during which she sings and converts non-believers. Following her death, Pope Urban decrees her to be Saint Cecilia