Part One
Rome is riven by factions, split principally between the republicans, loyal to the memory of the late Germanicus, and the followers of the Emperor Tiberius and his second-in-command Sejanus. When Tiberius calls for a statue to be erected in Sejanus' honour, the Germanicans are outraged.
Drusus, Tiberius' son, publicly insults Sejanus, unaware that Sejanus is planning to seduce his wife Livia and plotting to kill him. At a specially convened Senate, Tiberius and Sejanus consolidate their power over the Germanicans, accusing the old general Silius of treason on fabricated charges; and arresting the historian Cordus. Sejanus seizes this moment of high favour to propose to Tiberius that he might marry the newly widowed Livia. Planning to seize power for himself, he tries to persuade Tiberius to retire from Rome. But Tiberius stalls him. Sejanus' ambition has made him suspicious. He sets Macro to spy on Sejanus.
Part Two
Sejanus continues to persecute his enemies, setting his sights on Sabinus, and on Germanicus' widow Agrippina, and her sons Nero and Caligula who stand next in line. Rumour and counter rumour sweep the court. News of bad omens occurring at the site of his statue reaches Sejanus. Contemptuous of religion, he nevertheless makes an offer to the goddess Fortune but is enraged when she seems to snub him. Macro tricks Sejanus into thinking he is to be honoured with the tribunicial power, which would proclaim him to be Tiberius' heir. As the Senators compete for his favour, a letter from Tiberius is read out which is highly critical of his former associate. As the tables turn on Sejanus, his fall becomes inevitable.
