Resident Evil: Degeneration is the first full-length CG animation feature film based upon Capcom's Resident Evil video game. The main characters are Leon S. Kennedy and Claire Redfield, who appear together for the first time since Resident Evil 2.
The story takes place one year after the events of Resident Evil 4. Claire arrives at Harvardville Airport to meet a family she is aiding. Shortly after some time, the premises fills up with zombies, a plane also crashes into the air-port with zombies dropping out of the airplane.
The airport was locked down by the United States Marine Corps. Two Special Response Team officers, Angela Miller and Greg Glenn are joined by a government agent with experience of such incidents, Leon S. Kennedy.
After escaping the airport, Claire made a visit to WilPharma's research facility, WillPharma told Clarie before running off that WillPharma held the G-virus in their facility.
Claire calls Leon to update him about WilPharma's possession of the G-Virus
Leon and Angela arrive at WilPharma to find Claire. Suddenly, Curtis arrives at the garden. Not having much time left, he tells Angela that the government covered up some of the events in Raccoon City which kept his family from being saved (Curtis is related to Angela, brother and sister). A squad of marines storm the room, aiming at Curtis, believing him to be a terrorist. Curtis, having injected the G-Virus, mutates.
Curtis, fully mutated, attacks and kills all marines helplessly. Leon then arrives to save Angela from Curtis.
The building is then set to selfdestruct by the WilPharma computer system in an attempt to avoid the t-Virus and G-Virus's spreading causing another outbreak similar to Raccoon City.
Leon and Angela search for an escape route with Curtis attacking them both. Curtis manages to regain control, telling Angela to run away before he kills her. As the sections are being ejected, Leon and Angela climb up wreckage. Almost free from the drop, Curtis grabs hold of Angela. Leon shoots Curtis in the face, Curtis is sent flying down to the pit of WillPharma.
Leon and Claire say goodbye to Angela and leave. Meanwhile, news gets out that "TriCell Offers to Purchase WilPharma stocks". The film ends with Tricell employees in hazardous enviroment suits searching the underground ruins of the WilPharma, they discover a limb of Curtis's body infected with the G-Virus, which they sealed in a bio-hazard container.