Underworld: Awakening is the 4th film in the Underworld franchise, which sees Kate Beckinsale reprise her role as the sleek vampire Seline. Seline awakes to find she has been cryogenically frozen for the previous 12 years. During this time the humans have attempted to cleanse their world of vampires and lycans and are very much the dominant species again.
From here the story doesn’t really matter because there really isn’t much of one, and who goes to see these films for the story-line anyway? It’s best not to worry about the story too much, because if you do you will not be able to ignore the giant plot holes which litter the film.