It's about an Umbrella Corporation lady scientist who was exposed to the virus she was doing experiments on. After the expose, she becomes a giant mutated monster. While the Umbrella Corp. sends a team to rescue her & collect her research information, they encounter her & blast her to pieces.
The virus has evolved into such a stage that it can automatically transfers to any other living/dead creature which comes in contact with it. A cockroach, rat & then a crow/raven finally made their way to infect another human being (Soldier) after which he starts attacking his team members. Then again escaping his attacks, only 2 soldiers managed to drive away. But something happens in the vehicle they came in.