Picking up immediately after the previous film, RETRIBUTION, Alice (Milla Jovovich) finds herself alone in the ruins of Washington DC. She's attacked by a zombie, then a bat-like creature before being contacted by the computer entity Alicia/The Red Queen. The computer program wants to stop Dr Isaacs from killing the rest of mankind that's survived on the surface. You see, the Umbrella Corporation planned out the apocalypse and all it's members are in suspended animation deep beneath Raccoon City. Alice is told there's a cure to the T-Virus and that she has two days to retrieve it and release it into the atmosphere. Of course, it will kill everything that's been affected by the virus, including her. She's joined up by a group of resistance fighters which include Claire Redfield (Ali Larter) and some new characters, who all get slaughtered. There's lots of action, a return to "where it all began", and everything is explained concerning the true identity of Alice and how Dr Isaacs (Iain Glen) had survived. It all fit together well and is very logical, once you recall all the other movies in the series.
I suspect this is as much "The Final Chapter" as much as FRIDAY THE 13th: THE FINAL CHAPTER (#4) was the last movie in that series...