EDIT: Great minds think alike, rust!! /EDIT
I've cracked my old Library Data books open, and I've found something that might serve as an example:
The Reign of Arbellatra, the Third Imperium's 'Diocletion'. Young and stunningly attractive, the ruthless naval admiral leads a daring series of raids against the Outworld Coalition in the Marches (c.620). The PCs are part of some commando mission, redirected to rescue her crashed ship on an occupied world. They gain her thanks. The Second Frontier War ends when a new type of dreadnaught is rushed into battle, perhaps saving the PC's lives duing a hairy battle. The PCs see her ruthless streak at wars end when she hands over an Imperial world to the Zhodanis, despite that world treating her very well (the world she was crashed on perhaps?). End of war. End of movie #1

Hey, it's a trilogy!!
In movie style, we might have to fast forward, or compress the time period. In campaign play we might play one big session 'per campaign year'.
Movie Two. What's this one about? Arbellatra returns to the imperial core with the PCs in tow, (they created military characters in good old fashioned Traveller tradion, right?) and challenges the current emperor Gustav for the throne. He's a navy officer, and murdered the last emperor only two years ago, its how things get done in thecore these days… She defeats the Central Fleet with the crucial help of the PCs and their (nimble) scout ship at the 2nd Battle of Zhimaway (622). Maybe the PCs had to conduct recon, or find the location of the fleet, perhaps kidnapping Gustav, only to findhe is a double… but that the double can lead Arbellatra to the Central Fleet's secret deployment area. 2nd moviesare always weak,mine needs more pep!
Movie Three. With Gustav dead Arbellatra proclaims herself regent, not empress and says she hold out for the true ruler to step forward. She dispatches a search party for the blood descendants of empress Jacquline, last true emperor of the 3i. Of course the party get this job, sent out by Arbellatra herself, noexpensespared in a grand send-off with media, admirals, choirs, bands etc.
Then nothing. No support, following dangerous leads in deadly backwater worlds looking for rumours of lost descendants … The PCs end up facing off against a group of scary mercenaries when they make a miraculous discovery and actually find a long lost relative. Of course these guys are sent by Arbellatra, and headed by her scarred and super-evil chief of security, a battle-hardened Force Commander.
They may or may not get this descendant to Capital. Ever seen Babylon AD? Or Fifth Element? If they do history gets changed. Cool would be getting her to Capital in secret, aided by a Solomani plot who know she is a Solomani pure blood and see the new relative as away to seal the dominance of Earth and Sol oncea gain. On Capital, treachery abounds and in firece firefights the girl is killed or lost, the Pcshauled before a furious Arbellatra who 'tells them off'. Then pays them off with aship or something, and a promise to never speak of the girl …. Snow White?
Arbellatra is proclaimed empress in 629 her young 5yr old son Zhakirov, by her side. The end. (And at age 42 Arbellatra is still a stunning woman!)