(Operation Raccoon City's backstory)
Jill Valentine was a S.T.A.R.S. officer who was caught up in the Raccoon City Destruction Incident.
The Echo Six squad first meets Jill in front of the Raccoon City Police Department while she is being chased by Nemesis T-02. After Jill and the Echo Six team navigate the city to escape from Nemesis, Jill explains that she is an ex-S.T.A.R.S. member who stayed in Raccoon City to investigate some of Umbrella's more questionable activities. She then advises them to check out Raccoon City Hall in order to gain more information on Umbrella before parting ways.
After following up on Jill's intel about City Hall and gathering evidence against Umbrella linking them to the viral outbreak, they encounter her and Carlos Oliveira in front of the Saint Michael Clock Tower. After witnessing the destruction of their rescue helicopter, Jill and Carlos are forced to face Nemesis. Once Echo Six reaches the Clock Tower, they found out that Jill has been injured by Nemesis and hold him off while Carlos brings her to safety.
Jill appears in the game's Heroes Mode as a playable hero.