Act I: Caligula’s Despair
Following the death of his sister and lover Drusilla, Caligula goes missing. Three days later, he returns, distraught and dishevelled. He orders his slave Helicon to bring him the moon. Livia, Scipio, Mucius, Lepidus and Cherea ask Helicon if he has news of Caligula. Caesonia, Caligula’s wife, tells them that Caligula talks in his sleep about his dead sister. Caligula appears. The Roman people beg him to rule over them again. This he does, but in a completely different and terrifying way, passing absurd and brutal laws. Alone with Caesonia, Caligula reveals some of his insane plans. She is horrified, but reaffirms her love for him and promises to help him.
First Intermezzo: Caligula’s Dream
Act II: Caligula’s Game
Livia, Scipio, Mucius and Cherea are conspiring against Caligula, who appears to have gone completely mad. Caligula interrupts their plotting and invites himself to dine with them. The atmosphere becomes more and more uncomfortable. Caligula rapes Mucius’ wife, Livia, and forces Mereia to drink poison. Only Scipio remains uncowed by Caligula’s threats. He tells the emperor that he pities him in his depraved loneliness and leaves. Caligula makes the people acknowledge him as master of life and death.
Act III: Caligula’s Divinity
Caesonia and Helicon announce that a miracle is going to take place. Caligula isrevealed as Venus, who is to marry the moon, and everyone is forced to worship him. Helicon has intercepted evidence that proves Cherea is involved in a conspiracy against Caligula. Cherea is summoned and speaks openly with Caligula. The emperor confronts him with the evidence of the conspiracy. Cherea realizes that he could be put to death immediately, but Caligula proves his power over him by destroying the evidence and lets him go. The ritual dance for the moon goddess begins: Caligula forces everyone to join it.
Second Intermezzo: Caligula Dances
Act IV: The Death of Caligula
Caligula senses that his death is near. He commands Helicon once again to bring him the moon. He sends for four poets who are each to be given one minute in which to prepare a poem about death, which he will judge; a blow from his whistle means death for the speaker.The conspirators have just resolved that the time has come to act when Caesonia rushes in and tells them that Caligula is dead. As they begin to express their relief, Caligula suddenly reappears among them: it was a trick. The conspirators ask him if he has been ill, if they can help him. Mucius, foolishly, says that he would gladly give his life in exchange for Caligula’s, the emperor takes him up on his offer and orders that he be executed. Caesonia makes a last attempt to move Caligula; however, he demands her death as conclusive proof of her love and she allows him to strangle her. Helicon is stabbed when he tries to warn Caligula of danger. The conspirators storm the palace and murder Caligula.