This is a starting point for an adventure, a campaign maybe. The player characters are hostages.
As a boy, Aetius was at the service of the imperial court, enrolled in the military unit of the Protectores Domestici and then elevated to the position of tribunus praetorianus partis militaris, setting him up for future political eligibility. Between 405 and 408 he was kept as hostage at the court of Alaric I, king of the Visigoths. In 408 Alaric asked to keep Aetius as a hostage, but was refused, as Aetius was sent to the court of Uldin, king of the Huns, where he would stay throughout much of the reign of Charaton, Uldin's successor. Some modern historians have suggested that Aetius's upbringing amongst militaristic peoples gave him a martial vigour not common in contemporary Roman generals.
I cannot resist quoting the following, hoping to highlight the difference between the Roman Republic and the Rome of Aetius.
Mutual exchanges of hostages occurred when governments of approximately equal power wished to secure an agreement. Because bilateral exchange is a recognition of political equality, the history of Rome’s successful expansion provides few examples of such exchanges; Rome rarely recognized the political parity of another nation, and it is a striking fact that there is no surviving evidence for even a single instance of Rome’s involvement as an equal partner in a historical exchange.
The hostages are youngsters raised at court, they've probably somehow adopted the customs of their guardians. How about their outlook? The characters could be hostages from different powers, one of them wouldn't be an hostage at all, he or she could be a page or even a royal infant.
At some point, accidentally or not, the bridle is loosed on our characters, and their loyalty is tested. That may reek of For the Queen, but why not?
Or the challenging event may turn into an ad-hoc diplomacy match. The group must survive but each participant must do their best for their power. Or what they believe is the best for their power. They're youngsters, some of them are probably not mature enough to understand the great game.
The sudden freedom could also inspire the group to go on adventure, casting off all the moorings.