When the mighty Emperor Trajan throws his great games of 107 AD, the crowd is treated to a rare spectacle: female gladiators. The combatants are typically prisoners of war, but in one game, a Roman woman named Mevia makes history. She decides to trade her status as a free citizen of Rome to fight in the arena as a gladiatrix, a controversial and shocking choice that earns the enmity of Roman historian and satirist, Juvenal. Her choice illustrates the challenges of plebian life for women in ancient Rome.

One of the most famous doctor/scientists of the ancient world, Galen of Pergamon makes a name for himself as a physician for gladiators in the arena. But just as Rome's Empire reaches the height of its power and influence under Emperor Marcus Aurelius, a devastating plague sweeps through the city--and Galen catches the attention of Emperor Marcus Aurelius. Now it's up to this scientist to defend Rome from disease and keep the Emperor alive at all costs. This episode marks a turning point in the series, as barbarian attacks along Rome's northern borders intensify, beginning the long period of Rome's decline.