In 2179, Weyland-Yutani gave orders to the colonists to investigate the ruins of the Derelict spacecraft where they discovered thousands of Xenomorph eggs in suspended animation. Soon the eggs began to hatch and the facehuggers started to impregnate the colonists. The Xenomorphs soon established their hive within the processor due to its warm condition being perfect for incubating the Queen's eggs. After the colony was eventually overrun by the Xenomorphs, the remaining colonists were brought into the processor to serve as hosts for the eggs.
After the mysterious loss of contact with the colony, Weyland-Yutani sent the USMC, including Lieutenant Ellen Ripley, the sole witness of the Nostromo incident fifty seven years ago to investigate. After the Colonial Marines landed on LV-426, they investigated Hadley's Hope, only to find one survivor of the infestation. The Colonial Marines soon investigated the processor in search of the Xenomorphs' presence. Ripley realized that the Marines were right under the cooling tower and she informed Gorman, who was confused. Burke explained that the processor "is like a big nuclear reactor": and that using assault rifles and grenades could rupture it and cause a thermonuclear explosion. Gorman agreed and had the Marines hand their grenades and ammo over to Frost, reducing their arsenal to only flame units. The Colonial Marines disobeyed Gorman's order as soon as they were attacked by the Xenomorphs and used the assault rifles to fight them off. The surviving Marines were forced to retreat. As feared, the fight with the Aliens resulted in the colony reactor being damaged and leaving them with only a few hours before it explodes.
Ripley later came face to face with the Queen during her attempt to rescue Newt within the processor. Ripley threatened to destroy all of the eggs in the Royal Chamber if she and Newt were attacked, and the Queen signalled her circling warriors to let them leave. But, when one of the eggs hatched, Ripley incinerated the eggs with her flamethrower and shot the Queen's Eggsack with her grenade launcher. Enraged, the Queen detached herself from her eggsack and pursued the fleeing humans through the increasingly unstable structure. Ripley and Newt were rescued in the nick of time just before the Atmosphere Processor exploded. But the Queen clambered up inside the dropship's landing gear compartment at the last minute, and so escaped the nuclear meltdown that atomized her hive. The remaining Xenomorphs on Acheron were able to survive the Atmosphere Processor's meltdown and a second Queen soon emerged to take over the first Queen's place after she was killed by Ripley.