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.

Having learned that Vorenus' children are alive, Pullo sets off to find him in Gaul where he is again a serving soldier in Mark Antony's army. He had hoped to arrive before Octavian and Antony's armies meet in battle. Too late however, he is forced to find what is left of Antony's army in the mountains. He finds Vorenus alive and well, if somewhat battle worn, and they set off to find the children. The victorious Octavian plans his return to Rome. In Western Turkey, Brutus and Cassius amass their own army, now 9 Legions strong. In Rome, Servilia's attempt to kill Atia fails and Atia has her kidnapped tortured beyond what even her henchman Timon can stand.

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.

Inconsolable at the death of Brutus at Philippi, Servilia makes her final bid to gain the ultimate vengeance against Atia. Meanwhile, Eirene and Gaia have a major falling-out, prompting Eirene to demand that Pullo properly chastise the slave. When he does, the dynamic between the two of them changes in a violent and unexpected fashion. King Herod engages Mark Antony as a reluctant ally by offering a generous gift of 20,000 pounds of gold, and when Posca is excluded from sharing in the windfall, he engineers a move behind-the-scenes that will once again strain the uneasy truce between Octavian and Antony. Vorenus eldest daughter, Vorena, is blackmailed by Mascius into spying on her father after her tryst with one of his men is discovered. The end of two love affairs and a marriage in the house of Julii have major ramifications for life in the city and on the Aventine when Octavian insists on the courtship between Octavia and Mark Antony which irks both Atia and Agrippa. Also, a desperate move to assassinate Herod finishes the relationship between contentious siblings Timon and Levi when they have a falling out, and Levi gets killed by accident.