Corporal Dietrich was a member the United States Colonial Marine Corps, serving as a field medic. In 2179 she was a part of the platoon of Colonial Marines dispatched aboard the USS Sulaco on a rescue mission to the Weyland-Yutani terraforming colony "Hadley's Hope" on Acheron LV-426.
Mission to LV-426
In 2179, Corporal Dietrich and her platoon was sent to investigate the loss of contact with Weyland-Yutani's colony, Hadley's Hope, located on LV-426. Once the Sulaco arrived near the planetoid, Dietrich and the others are awoken from hypersleep. Dietrich got up next to her fellow squad mate, Drake, who complained to her that they don't get paid enough for this and proceeded to tell him not enough to wake up next to his face. Dietrich and the rest of her platoon were present during the mission's briefing by the squad's new commanding officer, Lieutenant Gorman. During the briefing, Dietrich listened to Ellen Ripley, the mission's consultant telling her encounter with a hostile creature that she and her crew encountered fifty-seven years prior, and how it killed them off. Ripley believes the same kind of creature are responsible for the lost of contact with Hadley's Hope and they will most likely encounter them once they land on the planetoid.
After landing on LV-426, the Marines arrived at Hadley's Hope and began their sweep of the complex to investigate what happened to the colonists. During one of the sweeps, Ripley and the Marines found a survivor from the colony, a young girl named Rebecca Jorden. They took the girl to the operations center where Dietrich tended to the girl and determined that she is physical condition is fine beyond minor malnutrition, although noted that she could not be so certain about the young girl's mental state. During this time, Rebecca, who went by the name "Newt", was asked by Ripley about what happened to the colonists and she told her and the Marines that they were all dead. Hudson managed to locate the colonists using their PDTs, tracing them to the colony's Atmosphere Processor, prompting Dietrich and the other Marines to set off to investigate and rescue any survivors.
Upon entering the Atmosphere Processor, the Marines discovered the Xenomorph Hive, Dietrich noted that the hive walls were made out of some sort of excretion. As the Marines made it further into the Processor, Lieutenant Gorman ordered them to give up their Pulse Rifle ammunition to prevent gunfire from damaging the Processor's reactor, only allowing them to be armed with Flame Units. The Marines eventually discovered the bodies of the deceased colonists cocooned on the walls, with their chests ripped open. Upon inspecting a cocooned colonist, the colonist then opened her eyes, which startled Dietrich, who called out to the other Marines that she found a live one. Dietrich immediately began medical treatment, ignoring Mary's desperate pleas for death, trying to reassure her that she was going to be alright. At that moment the Chestburster inside the colonist violently erupted from her chest, forcing Sergeant Apone to incinerate the body and the creature. The dying creature's screeches woke the Hive, and the squad's motion trackers began detecting movement all around them. The Marines immediately switched to infra-red scanning but still could not see the threat. Ironically, Dietrich questioned out loud whether their targets would show up on infra-red at all, just moments afterwards a Xenomorph Soldier sneaked behind Dietrich and immediately snatched the Corporal off the ground. In blind panic, Dietrich discharged her flamethrower. Unfortunately, Frost was caught in the line of fire and was incinerated along with the bag of ammunition he had collected, which also resulted in the death of Crowe from the explosion.
After Ripley and the remaining survivors had escaped of the disastrous ambush, Hudson discovered that both Dietrich and Apone's PDT data stream show that they were both still alive, although Ripley determined that they were both being cocooned and used as hosts to birth new Xenomorphs. Dietrich and Apone presumably died either from the Chestburster hatching or from the explosion of the Atmosphere Processing Plant's reactor.
Personality & Traits
Dietrich had a habit of insulting people when she had a chance, particularly those who liked to complain. But when it came down to business on a mission, Dietrich behaved professionally. When she found the live colonist on LV-426, she attempted to comfort the woman telling her she was going to get her out of there.
As a Marine, Dietrich was outfitted with the standard issue M3 Pattern Ballistic Armour for protection and a shoulder lamp attachment for illumination. As the squad's field medic, Dietrich also carried a field first aid kit on her. For protection, Dietrich used a M240 Incinerator Unit.