The plot of Resident Evil: Extinction revolves around Alice, who is now a skilled fighter and leader, as she navigates a post-apocalyptic world filled with zombies and other monstrous creatures. Along the way, she encounters a group of survivors, including a young girl named Becky (Oded Fehr) and a mysterious figure named Sergei (Terence Stamp). As they journey across the desert, they discover that the Umbrella Corporation is still active and is working on a new, more powerful virus.