Claire Redfield was captured by Umbrella, because she infiltrated their Headquarters. The man that actually captured her was named Rodrigo Juan Raval and she was sent to an isolated island called Rockfort. He let's her go when the island is attacked, and she meets up with Steve Burnside. His parents were killed by Umbrella, and he was held prisoner on the island. They split up. Claire gets to a computer and contacts Leon with the coordinates of where she is. He gets them to Chris, and Chris sets off to get there.
Steve and Claire eventually escape after encountering Alfred Ashford several times, who thinks he's 2 ppl; him and his sister Alexia. The real Aleixa is not around yet, but they are part of a family in which one of the Umbrella founders was in. The plane they escape onto goes into autopilot, and heads to Antarctica. They almost escape the place, but then the real Alexia awakes from stasis with a lot of power. Alexia made a virus 15 years ago called the T-Veronica Virus. She takes down Steve and Claire's vehicle, and it gets lit on fire.
Chris arrives at the prison island, but learns from Wesker that Claire's not there and tells where she is. Yes, that's right, Albert Wesker is alive. Chris eventually reunites with Claire in Antarctica, but she won't leave without Steve. But once she finds him, he changes in to a mutant thanks to Alexia Ashford, who injected him with the same virus she injected into her father a long time ago. Alexander Ashford turned into Nosferatu because of it. Steve comes back right before he slices into Claire's neck...and dies while saving her. Chris fights Alexia, and beats her. Now in CVX, Wesker takes Claire hostage and Chris goes after them. They fight it out after Wesker says he's takin Steve's body cause it has the T-Veronica Virus in it (actually he says T-Alexia Virus), and that he might even come back as Wesker did. Somethin splits them up though (Chris and Wesker), so Claire and Chris escape vowing to destroy Umbrella once and for all.