Rejected by Vorenus and Eirene and racked by guilt for the killing of Eirene's fiancé out of a jealous rage, Pullo has sunk to working as an assassin for the gangster Erastes. When Pullo gets arrested for killing one of Caesar's popular opponents, he condemns himself by refusing to name who hired him, despite Octavian's attempts to defend him.
Meanwhile, Vorenus finds his new official duties as magistrate tedious, especially when he gets caught between Caesar and the demands made by veterans' spokesman Mascias.

Vorenus' defense of Caesar lands him in an unexpected position of power within Rome. Meanwhile, Servilia hurls the final obstacles in her ambitious and complex revenge plan against Caesar and Atia.

Caesar has been murdered, Mark Antony emerges from the Senate in shock, only to face Quintus Pompey and his thugs, who immediately follow him to try to kill him. Brutus returns home shaking after the murder. His mother is already plotting the return of the Roman Republic. Titus Pullo asks Eirene to marry him and she accepts. Erastes Fulmen kidnaps Lucius Vorenus' children and sister-in-law.
Mark Antony proposes an amnesty to the rest of the senate to keep the peace and allow the Republic to continue. Vorenus says goodbye to Niobe while Rome says goodbye to Caesar. Vorenus and Pullo track down Fulmen to a bath house, where he tells them he killed Vorenus' family.

Even though his wife and children are avenged by the Erastes killing, Lucius Vorenus keeps mourning for over a month till Pullo gets Marc Antony who scolds him for Caesar's death and the continuing bloody Aventine gang riots that have resulted in the gangs wanting to fill the void left by Erastes sudden demise.
Octavian is loosing patience with Mark Antony for payment of Caesar's inheritance. Meanwhile, Queen Cleopatra of Egypt arrives in Rome to pay her respects to Caesar and she also negotiates with Antony's military protection for her Pharaonic throne.

With the defeat of the Egyptian fleet at Actium, Mark Antony and Cleopatra retreat to their palace and await their fate. Believing that Cleopatra has taken her life, Mark Antony decides follow her into the afterlife. She has other plans however and is quite prepared to negotiate with Octavian if there is any possibility her life and those of her children will be spared. Cleopatra asks Vorenus to take her son Caesarian to safety and Octavian sends Pullo after them. The old friends are soon together again.