(Covers information from Anderson's universe)
In 2002, with support from her brother, Lisa sought and gained employment with Umbrella, assigned to the computer security division working out of The Hive. The purpose of this being to recover incriminating evidence of Umbrella's crimes, a task she was well suited to. She was forced to work closely with Dr. Barr's creation, the Red Queen, and found that duty quite unpleasant.
While in the Hive, Lisa created a security protocol requiring all employees to change their password for the computer network every eight days. She knew that most people would forget, which was another part of her plan. When someone forgot to change their password, they were locked out of the system until Lisa could help them. After resetting their password, Lisa would get a momentary glance at whatever information the person in question was trying to access, in the few seconds it took the Red Queen to realize that she didn't have clearance to see the data. It was this method by which Lisa hoped to secure the evidence against Umbrella. It was also by this method that she came to conspire with Janus Prospero.
When Janus, the Hive's security chief, requested help with the password system, Lisa readily complied, eager to see what data the head of security would access. What Lisa didn't know was that Janus had set the whole thing up to determine Lisa's plan.
After a lunch in Raccoon City, Janus showed Lisa security footage of Lisa peering intently at her monitor during the password trouble-shooting session, admitting that she had realized what the other woman was up to. This was the preface for a more shocking revelation: Janus was also planning to move against Umbrella, and wanted Lisa's help to do it. She promised to help obtain data on the new biological weapon, the t-Virus, in exchange for Lisa's promise to bring Umbrella down, a plan which Lisa readily agreed to.
Unbeknown to either of them, Janus's partner, Spence, had eavesdropped on their conversation, and was planning himself to steal the virus. He released the virus into the Hive's air conditioning system and made his escape. The Red Queen, in an attempt to stop a disastrous viral outbreak, sealed Lisa's office and filled it with halon gas, suffocating everyone within.
Hours later, as Umbrella's commando team came into the Hive to investigate the incident, Lisa's own brother, Matt went in with them to find her, or some of her gathered evidence. He was met by Lisa's corpse, reanimated by the t-Virus, who attacked him. Lisa was killed for the final time by Janus, who bashed her skull in with her own paperweight.