After Conan and Ai Haibara were hunted by the Organization, they were rescued by mercenaries sent by Oswell E. Spencer, the creator of Umbrella Corporation. But there was a price: they had to join Umbrella Corporation and use APTX4869 to modify the Progenitor Virus. So Conan and Ai Haibara arrived in Raccoon City, unaware that a crisis was brewing.