Rome, AD 30–31. Tiberius has retired to Capri. Sejanus consolidates his hold on power in Rome by engineering the banishment of Agrippina and her eldest son Nero and having her other son Drusus arrested and starved to death. Sejanus has divorced his wife and approaches Tiberius about marrying Livilla. Tiberius refuses as the marriage would mean Sejanus would be elevated in rank but suggests that he could marry Livilla's daughter Helen. An outraged Livilla attempts to poison Helen. Antonia discovers letters from her daughter to Sejanus, implicating them both in several deaths and urging Sejanus to murder Tiberius. Claudius smuggles the evidence to Tiberius. At Caligula's suggestion, Tiberius orders Macro, an officer of the Guard, to carry out the execution of Sejanus, his followers, and his family. Claudius barely escapes by divorcing his wife. Antonia locks Livilla in her room and sits outside the door until Livilla dies of starvation. Delighted by Caligula's perversity, Tiberius appoints him his heir.
