Legionnaire Titus Pullo has been reprimanded for breaking structure during a battle in Gaul. However, when the army’s gold standard gets stolen, Lucius Vorenus takes Titus Pullo from his prison and the two set off to try to find the standard. Meanwhile, Pompey contemplates what he should do about Julius Caesar’s rising fame, while Julius Caesar deals with startling news amidst the plummeting morale of his troops.
Mark Antony heads back to Rome in order to speak on Caesar’s behalf, in which Lucius Vorenus and Titus Pullo are stationed to go with Mark Antony, as well as the recently rescued Octavian. At Rome, Lucius Vorenus heads home to see his family for the first time in eight years while Pullo looks for some pleasure, though when Pullo kills a man who tried to cheat him in a game, he sets off a chain of events that could potentially bring down the republic.
Julius Caesar is making his way towards Rome, though Lucius Vorenus is contemplating while the army has encountered so little resistance during their patrols. In Rome, Pompey begins ordering a retreat of his forces and he assigns his best men to take the entire city’s treasury to their planned destination. Meanwhile, Atia plans on using foul play in order to force her daughter to stop loving a lower class citizen.
Julius Caesar is attempting to fully establish his position in Rome, in which he decides to attend a party that Atia is holding in order to celebrate his victory. Meanwhile, Lucius Vorenus decides to hold his own party since he has retired from the military and is working as a civilian businessman, while Titus Pullo contemplates what he should do with all of the gold that he found, though he soon encounters Pompey’s son and he takes Vorenus’ advice to take him to Caesar.
Pompey decides to send Caesar another offer in hopes of limiting his power, in which Caesar decides to take some time to think upon the issue, despite Mark Antony’s objections. Meanwhile, Lucius Vorenus refuses to allow some thugs to harm a citizen in debt, which causes him trouble in his job as the thugs he threatened worked for the biggest crime boss in Rome. Titus Pullo also is hired as a military tutor for Octavian, though he discovers that Octavian isn’t as helpless as he seems to be.
Caesar is in the middle of a fight with Pompey’s forces when he realizes that he’s become severely outnumbered. He sends a request to Mark Antony in hopes of having him come with reinforcements, though Mark Antony is deciding whether or not he should join Caesar or try to stay as Rome as a ruler himself. Meanwhile, Niobe discovers that the man she loved while Vorenus was gone has recently been murdered, though such turns out to be the catalyst for her renewed love for her husband.
Lucius Vorenus and Titus Pullo are lost at sea after their legion’s ship was destroyed on their way to help Julius Caesar’s army, though they have a chance encounter with someone they know. Meanwhile, Pompey decides to send order a full assault on Julius Caesar’s camp in an attempt to destroy him once and for all, though the battle goes rather unexpectedly. Back in Rome, Atia is attempting to win the favor of Servilla as she believes Caesar will lose and she needs protection from a supporter of Pompey.
Julius Caesar has chased Pompey to Egypt in hopes of capturing him once and for all, though he discovers that King Ptolemy XIII has done something unspeakable to his former friend. Meanwhile, Lucius Vorenus and Titus Pullo are assigned with the task of finding Ptolemy’s sister, Cleopatra, as Julius Caesar has plans with her. However, when Lucius Vorenus gets a strange request from Cleopatra, he must contemplate defying his duty in order to remain loyal to his wife.
Julius Caesar and his legions have finally defeated all the traitors of the Republic and he heads back to Rome where he receives a glorious welcome. Meanwhile, Lucius Vorenus and Titus Pullo get into an argument with a local crime boss who isn’t happy with the way Vorenus had previously treated his men.
When Julius Caesar is formally proclaimed Dictator by the Senate of Rome, he declares that the war is over and that Rome celebrates his triumph through five days of feasts and games. Titus Pullo contemplates taking Eirene as his wife in hopes of settling down and living a nice life, while Lucius Vorenus runs for municipal magistrate with Posca’s help. Meanwhile, Octavian tries to convince his sister to return home, while Servilla attempts to gather enemies of Caesar in hopes of convincing them to tack action against him.
Lucius Vorenus is asked by Caesar to convince a veteran soldier to personally accept a large severance in exchange for agreeing to make the rest of the veterans calm down. Meanwhile, Titus Pullo murders a famous critic of Julius Caesar and he is sentenced to death in the arena when his lawyer fails to defend him properly. Octavian attempts to persuade Caesar to pardon Pullo for his crimes, though when his requests are ignored, Titus Pullo’s fate seems inevitable.
Due to their heroic feats in the arena, Titus Pullo and Lucius Vorenus are praised as heroes throughout the entire city. Despite Julius Caesar’s desire to punish them for their actions, their fame and reputation causes him to think otherwise, so he formulates a plan to ensure his own safety while rewarding Lucius Vorenus. Meanwhile, Titus Pullo attempts to ask Eirene to forgive him, as he plans to start a family with her, while Brutus and the rest of his cohorts put into motion their plan to assassinate Gaius Julius Caesar.
The second season begins shortly after Caesar's murder. Octavian devises a plan to keep his family from fleeing the city, news that Antony happily delivers to a nervous Brutus. Meanwhile, Vorenus mourns Niobe's death but curses his children, and Pullo and Eirene get married without knowing what's happened back in Rome.
As gangs fight for control on the streets of Rome, Vorenus is called upon to undo some of the damage that he's done. Cleopatra pays a visit, bringing with her her son and Octavian becomes increasingly impatient with Mark Antony over the money he's owed.
Pullo tries in vain to persuade Vorenus to prevent a war among Aventine gangs; Antony's designs on Gaul elicit a shocking proclamation from Cicero to the Senate; Servilia enlists the opportunistic Duro to end an old feud; Brutus wrestles with his demons while seeking support in Bithynia.
Pullo races to find Vorenus with news of the fate of his children; Servilia pays a price for trying to eliminate a rival; a victorious Octavian sends word he's returning to Rome with his army, which comes as a surprise to Cicero; Timon grows weary of doing his mistress's bidding.
After his adventures with Antony and Pullo, Vorenus comes back to face the merchants of the Aventine Collegium; a pair of former foes reconcile their differences.
Vorenus is ordered to prune the ranks of Rome's elite; Brutus and Cassius prepare to face the recently allied Octavian and Antony in the Battle of Philippi; Levi and Timon create mayhem at a synagogue; Pullo thwarts Cicero's attempt to warn Brutus.
Octavian's campaign for a more virtuous society hits hardest in his inner circle; Vorenus's efforts to solve a gold robbery leave a bitter taste of betrayal; Pullo turns his grief about a personal loss into anger at a new enemy; Timon leaves Rome with his family for Jerusalem.
The people of Rome are starving. There have been many grain shortages over the past few months, but things have gotten particularly bad. In hopes of keeping the people from openly rebelling, Octavian sends Atia and Octavia to Alexandria in order to negotiate a deal with Mark Antony, though his real reasons for their trip is soon revealed. Meanwhile, Titus Pullo and Lucius Vorenus must try to keep the peace amongst many of the mercenaries who are in Rome.