Probably way too long for a loading screen, but here's my take:

The twenty-five million people dwarf planet of Setra, situated at the border of Imperial territories in the Outer Rim, fervently maintains her desire to remain neutral in the Civil War. However, Imperial authorities have recently begun suspecting that the planet's authorities harbour unfortunate sympathies - Alliance bases are close by, and hushed communication between rebels and the planet's ruling body indicates that a covert alliance might be underway.

For the Imperials to seize control of the planet preemptively is not possible, however. The planet maintains a decent military force, and a full-scale invasion and occupation would put too much of a strain on the meager Imperial presence in the backwater sector. Knowing this, Imperial commanders decide to carry out several surgical strikes on Setra's agricultural industry, doing as much damage as possible and hopefully forcing the world to become dependent on provisions imported from Imperial authorities.

Two days later, Setra's Early Warning Systems pick up Imperial ships entering orbit. 60 000 storm troopers are about to disembark, with orders to capture the farms, burn the crops, destroy the farming equipment and food stores, and evacuate before planetary authorities respond in full force and destroy them. Setra hurriedly scrambles her forces, and a high stakes engagement is about to begin...

In short, Setra, lying on the border of Alliance-Imperial space, wants to join the Alliance. The Imperials can't invade her, so they hatch a plan to destroy her food production capabilities so that she has to import food from off-world Imperial sources, leaving her, essentially, a hostage at the mercy of Imperial goodwill.

Imperials need to capture the farm before their tickets run out. Setra's armed forces (Alliance) needs to hold until this time.