Part I
Holofernes, the general of the Assyrian King Nebuchadnezzar, prepares the army for the storming of the city of Bethulia. Holofernes is sure of victory and inspires courage in his soldiers. Vagaus, the general’s squire, announces the arrival of a beautiful woman from Bethulia. She wants to speak to Holofernes personally, and he agrees to the stranger’s request. The woman, Judith, begs him to spare the city and its inhabitants. Holofernes is enchanted by her looks and her voice and invites Judith for a private dinner. After some reluctance at first, Judith follows him to his residence.
Part II
At the dinner, Holofernes toasts Judith's beauty while she tries to keep him at bay. He promises to keep the peace in exchange for her love. As he gets more and more under the influence of the wine, the general becomes overwhelmed by sleep. Judith grabs her chance and decapitates Holofernes with his own sword. She and Abra, her handmaiden, place the head in a bag and flee from the Assyrian camp. Upon their return to Bethulia, the citizens and the high priest Ozias hail Judith as a heroine.