Rim was a human colony world of the 2170's, overrun by a Xenomorph outbreak.
Ten years before the Earth Infestation, a family exploring the crash site of a downed alien spacecraft, returned to the Rim colony with a medical emergency. The father, who had discovered a clutch of Alien Eggs, had been infected by a Facehugger. The creature gestating inside him soon hatched, quickly spreading the Xenomorph infestation throughout the colony.
Several weeks passed before a squad of Colonial Marines arrived at Rim to investigate, losing half their number to the Xenomorph threat in their first encounter. Marine Corporal Wilks and a ten year old girl named Billie were the only survivors. Evidence of the Xenomorph infestation was covered up and the deaths attributed to the explosion of the colony's reactor.
- Billie's experiences on Rim mirror that of Newt on LV-426. Newt's further adventures after Aliens were thrown out of continuity after her death in Alien3. The planet Rim and the characters of Billie and Wilks are retcons of LV-426, Newt, and Hicks, respectively.