Hmmmm..... Thousands of years ago, the capital ship Rhiannon was fitted with an Experimental Warp drive, and engaged it while in orbit around Abraxis IV. It turned out that instead of neutralizing the destabilizing effects of a gravitational field on warp generators, the E-drive amplified the instability, with disastrous effects. Both Rhiannon and Abraxis IV (yes, the whole planet) were sucked into warp space and presumed to be lost forever.
But, last Thursday, a warp instability was detected near an old asteroid mining base, and early on Friday morning, a planet which appears to be Abraxis IV was ejected from warp. Rapid-deployment scout robots have confirmed the locations of major cities, roads, etc -- and also spotted the ship Rhiannon, downed on the planet and apparently mostly-intact.
It is not known how much subjective time has elapsed on the planet, nor whether it has been colonized by creatures native to the warp-space environment or whether any humans (or their mutated thousandth-generation descendants) might still survive there. You were dispatched with a crack team of troubleshooters (people who shoot trouble with REALLY BIG GUNS) with this mission: First, assess, report, and if necessary neutralize any threat to the empire. Second, get to the Rhiannon, board it, and dismantle the E-Drive before the local warp instabilities recharge its core and it throw the planet back into warp.
Something like that maybe?