Sherry Birkin was one of the few survivors from Raccoon City. When she was only a a child Leon S. Kennedy and Claire Redfield had rescued her from the infected City, along with saved her life when she was injected with the G-Virus. By the time they had given her the cure, the virus had already adapted to her blood. Once Leon and Claire had gotten out of the City Claire headed out while Leon and Sherry had been picked up by government agents. After discovered about the virus the government began testing and kept her locked up because of Albert Wesker who wanted the G-Virus. Once he was dead the government allowed Sherry to become and Agent of the DSO. That's when later she was given her mission out in Edonia to get Jake Muller, Albert Wesker's son, out of there safety. He had the vaccine for the C-Virus in his blood.