The village is controlled by a cult whose members are infected with Las Plagas, a dangerous parasite. Bitores Mendez leads the village, and Leon meets Luis Serra, who has knowledge about the infection. Ashley is also held in the village, and Leon is determined to rescue her.

The castle is controlled by Ramon Salazar, a loyal servant of the cult. The enemies here are tougher, with some wearing heavy armor, and Ashley is captured once again. As Leon fights to rescue her, he also encounters Luis, Ada, and Krauser, while solving puzzles throughout the castle.

Osmund Saddler, the island's boss and cult leader, plans to use Ashley to take control of the U.S. On the island, Leon faces enemies equipped with guns, shields, and massive monsters. Ada Wong also appears, offering crucial assistance to Leon during his mission.