Atia and her family have stayed behind when Pompey and others fled and she now throws a party for her triumphant uncle, Julius Caesar. She clearly has her sights set on the great leader and is puzzled when he sends her a guest list that includes Servilia of the Junii. She soon finds out why. Pompey wants to find out what happened to the gold from the Roman Treasury and sends his son Quintus to Rome to find out what happened. They go directly to Vorenus' home but he has no idea what they are talking about. Pullo arrives however and Vorenus tells him to go directly to Caesar himself and explain. Octavian meanwhile learns of one of his uncle's secrets.

Caesar contemplates Pompey's counteroffer. Vorenus continues to struggle as a businessman and must reevaluate his career choice. Atia schemes to come between Caesar and Servilia and Pullo seeks Octavian's help.

Caesar pursued Pompey to Greece but the tide has turned and it's Caesar who is on the run. He contacts Mark Antony, who he left in charge in Rome, to come and join him with the 13th Legion but Antony seems to be in no hurry. Vorenus has re-enlisted in Antony's Legion and he and Niobe have begun to renew their marital relationship. The presence of Niobe's sister is the only sour note in their house. Pullo meanwhile continues to train young Octavian in the use of arms and the boy's mother Atia is so pleased with his development that she decides he should take another step to manhood and orders Pullo to take him to a brothel so he can have his first sexual experience. Atia also continues with her scheming ways and believing that Caesar is done for, decides she had better make friends with Servilia.

As they try to reach Caesar in Greece, the shipwrecked Vorenus and Pullo confront an unexpected dilemma. Back in Rome, Atia again sends Octavia to beg protection from Servilia, who complies readily to encourage her growing friendship with Octavia. As they prepare their counterattack against Caesar, Pompey's Republicans begin to squabble over both the anticipated spoils and the method of finishing Caesar off. Niobe's sister Lyde comes back to see her and comforts her over Vorenus's disappearance. Badly outnumbered, Caesar and Antony make their stand at Pharsalus. On his arrival in Egypt, Pompey is greeted by a Roman veteran.

The defeated Cato and Scipio fall back on the African city of Utica after the Battle of Thapsus where they decide to end it all. Caesar, after two years of fighting in Greece and Egypt, returns to Rome and receives a hero's welcome. Meanwhile, Servilia's cold rage against the Julii clan makes Brutus's submission to Caesar even more painful. Octavian returns home from military school and Caesar, impressed with his nephew's incisive political acumen, appoints him a pontiff despite his youth. Having opened and operated a profitable butcher shop, Niobe and Lyde get the reluctant Vorenus and Pullo to join the trade, but Vorenus again crosses paths with the thug Erastes, now the crime lord of the Aventine. Learning of Caesar's secret "affliction," Servilia persuades her lover Octavia to cajole her brother into revealing more, but she only learns Niobe's secret instead. Servilia motivates Octavia to try again by other means, with dreadful consequences for both sister and brother. Pullo's affection for his slave Eirene deepens. Enraged at Servilia's manipulation of her children, Atia enlists Timon and his band of thugs to retaliate, thus escalating the term 'catfight' to a very different level.

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

In the wake of Caesar's death, Mark Antony considers a move north, while Vorenus issues a curse he soon regrets.

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 losing patience with Marc 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 in exchange for valuable grain shipments. But she gets dismissed as a whore when she demands that her four-year-old son, Caesarion, be recognized as Caesar's legal son. Yet the uninvited pair of them is welcomed by Antony at Atia's party. Abusing a truce in the name of the goddess Concord and smashing up her statue, Vorenus imposes as 'son of Hades' on the gang captains a peace, paid off by Antony so trade and politics on and near the Aventine no longer get disrupted. After his mother Atia and sister Octavia tell him to accept Antony denying Caesar's legacy and laugh at his ambition to provide Rome the leadership it needs, Octavian borrows against his vast inheritance to buy popularity by paying for Caesar's lavish bequests to the populace; Antony violently refuses a political deal with him. Octavian then leaves home and retires to Campania with General Agrippa. Cicero and Brutus' mother, Servilia, hope this strife among the Julii clan will allow their party to return to Rome. Also, Timon's long-lost brother, Levi, arrives back in Rome wanting his help to make a new life for himself.

Lucius Vorenus, the power-hungry "Son of Hades", controls the Aventine but practices a pointless, beastly reign of terror, coming down hard on gang captains for futilities, and nearly ruins his friendship with Pullo, whose efforts to calm things down are mistaken for disrespect and disobedience, even starts a fight once he learns the truth about Niobe; Pullio leaves Rome disgusted. After Atia convinces Marc Antony the governorship of ghastly Macedonia after his consulate would not only be unpleasant but leave him exposed to his dangerous enemies, he puts the heat on senatorial leader Cicero to give him Gaul instead, which once was the base for Julius Caesar's coup d'état. The slave Duro endures male prostitution but most arrogantly demands extra pay and even a kiss from Servilia as it will take more time to commit the planned murder in Atia's home. Marc promises Atia not to hurt Octavian, whose recruiting he calls a joke, after putting down his party's expected plot. Brutus has a hard time controlling himself while soliciting the Bithynian king's financial support to raise an army. Instead of proposing Antony for governor of Gaul, Cicero sends an extremely insulting speech and joins Octavian's growing army.

Vorenus and Pullo return to the Collegium in Rome with Vorenus' family, but some of the "changes" that Pullo had warned him about regarding his two daughters Vorena both the Elder and Younger, as well as his wife's son, begin to manifest themselves into hostility and resentment. But Vorenus is completely oblivious to this, and is too blissfully happy to return to the role of 'father'. Meanwhile, Octavian finally returns and manages to negotiate the Senate Consul's seat from a scheming Cicero, but in spite of his promise to 'faithfully follow' the older man's counsel, Octavian proves that he certainly has a mind of his own, vowing to hunt down and kill the assassins of Julius Caesar, much to Cicero's consternation. Elsewhere, Brutus and Cassius receive news that might prove useful in staging a triumphant return to Rome, as well as the ultimate defeat of both Mark Antony and Octavian's forces. Also, Atia has a reunion with her son that is strained to say the least, but there is a tentative reconciliation between them. And another, much less stressful reunion between two lovers, Octavia and Agrippa, who saves her from an attempted date-rape at an orgy party, will bring about an unforeseen alliance between two formerly mortal enemies.

Cicero is finally undone by his duplicity in the form of Titus Pullo, acting upon Octavian's request to assassinate all supporters of Brutus in Rome. Pullo and Vorenus enjoy a happy if counterfeit outing with their families in the countryside to hide their assassin mission. Vorena the Elder's dangerous dalliance with one of Mimeo's men continues, and the torrid affair between Octavia and Agrippa escalates. Atia's casual cruelty to ask for the assassination of people she doesn't like results in complete disaster for Octavia's friend Jocasta. Elsewhere, the headstrong Levi engages Timon in a plan to assassinate King Herod by recruiting in the synagogue where they worship. Disastrously out manned, Brutus and Cassius engage the combined legions of Mark Antony and Octavian, and confront their fates in the ferocious battle at Philippi.

Seven years have passed since Antony's departure from Rome, and the former commander, dissipated and debauched - held in thrall by the charms and sexual prowess of his new bride, Cleopatra, withholds precious shipments of grain from Rome, where people die in the streets from hunger. Unable to incite a war with Antony and Egypt without committing political suicide, Octavian sends Atia and Octavia to Alexandria to mediate and reason with Antony; a strategy which proves predictably unsuccessful. However, former Roman senator Posca and his wife, Jocasta, flee Alexandria with Atia and Octavia to Rome where he provides Octavian with all the ammunition he needs to bring about a war with Antony and Cleopatra. Meanwhile, Pullo has taken over the Avantine gangs of Rome. But later, a fatal blow is stricken to the torrid affair that has continued between Pullo and Gaia, as karmic debt comes to call when she saves him from the sadistic Memmino, but gets fatally wounded, and she lets it slip to Pullo that she was the one who poisoned Eirene. Octavian asks Pullo to join him in the campaign against Egypt, and Pullo agrees without question, hoping to reunite and redeem his blood brother, Vorenus, who continues to stand by Antony's side despite his growing contempt for his commander. Octavian calls for war against Antony in the Senate, and is met with thunderous approval.

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 but are waylaid by bandits. With Vorenus severely wounded, Pullo takes him back to Rome for what he hopes will be a happy reunion with his children.