The Raid on Aiur was a United Earth Directorate operation which occurred shortly after the defeat of the Terran Dominion on the surface of Korhal. Jim Raynor and a protoss task force had rescued Dominion Emperor Arcturus Mengsk from the UED.
The UED forces followed the fugitives to Aiur, where they discovered Raynor's weakly-defended command center near a large protoss base and a "fully functional" but inactive warp gate. The protoss had surrounded the warp gate in an effort to protect it from the zerg, but the zerg appeared to be passive. The UED cleared out a suitable home base from the zerg who occupied it and settled in for a siege. The Captain was ordered to directly assault the protoss, while Duran would hold off the zerg to the northeast. Stukov and DuGalle would also prevent zerg from approaching from other directions.
When the warp gate was activated, its powerful psionic energies awoke the zerg, who began to attack indiscriminately. Nonetheless, the UED slowly defeated the protoss, even destroying Raynor's command center. Raynor and Mengsk flew away in a dropship towards the warp gate, with the UED in hot pursuit.
Stukov detected a wave of zerg attacking from the northeast, but Duran had moved his forces out of place. Duran claimed his equipment wasn't detecting the zerg, and perhaps there was a problem with Stukov's equipment. Then he claimed his communications equipment wasn't working, and cut off the transmission.
The zerg interfered with the UED operation, allowing Mengsk and Raynor to escape. The warp gate then self-destructed.
Stukov told the Captain that he must leave, as he had a personal matter to take care of.