Framed for crimes against the country, the G.I. Joe team is terminated by Presidential order. This forces the G.I. Joes into not only fighting their mortal enemy Cobra; they are forced to contend with threats from within the government that jeopardize their very existence.

The story of the Arthurian legend, based on the 'Sarmatian hypothesis' which contends that the legend has a historical nucleus in the Sarmatian heavy cavalry troops stationed in Britain, and that the Roman-British military commander, Lucius Artorius Castus is the historical person behind the legend.

Season two's storyline picks up right where season one left off: with the 44 B.C. assassination of Gaius Julius Caesar and the near-simultaneous death of Niobe, wife of Caesar's faithful bodyguard Lucius Vorenus. Diverted from his post after learning that Lucius, his assumed grandson, was in fact Niobe's illegitimate son, Vorenus now descends into near-madness over his failure to protect Caesar, his role in his spouse's death, and the rumored murder of his estranged daughters.

公元前52年，罗马共和国正值鼎盛时期，执政官庞贝（里克•沃登 Rick Warden 饰）坐守都城，盟友凯撒（塞伦•希德 Ciarán Hinds 饰）征战高卢。期间，第13军团屡立战功，主将乌里纳斯（凯文•马克德 Kevin McKidd 饰）有勇有谋，手下波罗（雷•史蒂文森 Ray Stevenson 饰）虽嗜酒如命，却忠肝义胆。适逢凯撒得胜，屋大维遵母命赴前线慰问，不想途中遭劫，被经过的乌里纳斯和波罗救下。13军团凯旋，乌里纳斯与阔别8年的妻子相见，却各怀心事。波罗偶然间发现了乌里纳斯妻子红杏出墙的事实，为了保护长官的名誉，波罗在屋大维的帮助下，逼出了真相。凯撒准备独揽大权，一直等待时机。庞贝看出了他的野心，与元老院众人商议，其中以西塞罗为首的贵族势力，坚持认为凯撒为共和国叛徒，应诛杀之。而此时，凯撒的大将安东尼（杰姆斯•鲍弗 James Purefoy 饰）接任了护民官，与庞贝一伙展开周旋……