Hiding out in a resident's attic for most of the 30 days, and slowly losing members of their gang one at a time, they don't give in to the vampire's tricks to lure them out. Living off supplies they looted during a whiteout storm, they notice a morse code message from Billy's house (the Deputy). Getting to his place, they find he's been living on his own after murdering the women in his family (I think) before the vampires can get to them, and has obviously gone a little mad.
They get to the main power station with the other survivors, who don't feature too much, except Stella who somehow finds a little boy (or girl) who has survived all this time just wandering around town and they hide under a car.
In the power station a vampire attacks Billy. Eben kills it, and then turns on Billy with his trusty axe before he becomes too powerful.
The Vampires know that their time is up soon, so they start to burn the town. The flames are getting closer to Stella. Eben injects himself with some of Billy's vampire blood, and then goes out to meet the bad guys. He fights with the vampire leader, finally sticking his fist through the head of the bad dude. The other vampires just leave -- but what happened to the stranger (Ben Foster)? Must have missed that bit. But it seems he got a better part in another movie and just leaves early.
Stella is rescued. She sits next to Eben as they watch the sun rise and he is burnt alive.