Nero of course indignantly refuses to make this sacrifice.—Agrippina persists in her demands and carried away by her violent temper and her contempt for her false and treacherous son she commands him, either to give up Acté, or to give back the imperial power to his mother, as she alone made him, what he is.—Nero enraged shows himself as the ruler and the despot and so terrifies her, that she tries to retract her evil words and begs his pardon.
Tigellinus, Nero's friend and confidant, has heard her last words. He excites his master's hatred against his false mother still more, and they decide to take vengeance on her at some favourable time.
Hearing Acté singing in the vestibule Tigellinus leaves Nero, who receives his lady with open arms. A charming love-duet closes the first Act.—
In the second Act Marcus, an old Christian Patriarch, meets Acté in the gardens of the Palatine at night and wins her over to his faith. She promises to join the Christians, and to this purpose calls her slave Parthos, whom she persuades to guide her to the cave of Marcus.—After having given him a ring, Nero's love-token, to deliver to Caesar, she bribes Parthos, to swear, not to betray her secret, by making over to him all her worldly goods.—
Unfortunately this interview has been witnessed by Agrippina from her hiding place in the bushes, and she decides to make use of her discovery against her son.
When day breaks a grand festival takes place in the gardens. Agrippina hails her son, and seeing him alone she sweetly asks where his faithful companion Acté is.—Nero at once sends Tigellinus in search of her.
A beautiful ballet is now danced, and afterwards Caesar himself takes his lute and sings a hymn in praise of Venus, the Goddess of love.—He has hardly ended, when Tigellinus rushes in and exclaims that Acté is not to be found.
Nero storms and Agrippina, pretending to know nothing, suggests that Parthos should be questioned. The poor slave is dragged forward; he denies any knowledge of Acté's whereabouts, but her ring is found upon him. This he tremblingly gives to Nero, declaring that Acté gave it to him to return to Caesar.—Tigellinus says, that the slave evidently knows more than this, and Nero orders him to be tortured. While the wretched Parthos is being led away Agrippina declares defiantly, that she alone knows where Acté is, and offers to tell Nero on the condition, that he will restore to her the imperial power, that she covets. Nero, enraged beyond measure orders Tigellinus to keep his mother as a prisoner, until she reveals Acté's hiding-place.
He then turns to the frightened spectators and with the words "My will is law, I am Caesar and will remain so for ever" the Act closes.