“When a vampire master attempts to escape the mouth of hell, a reluctant new girl teams with a small group of nerds to stop the powerful bloodsucker from unleashing hell on earth.”

The series was more about the ongoing fight, week in week out, than the last big fight to prevent the big vampire from being resurrected.

Perhaps:
When vampires attack her small town, a reluctant new girl teams up with a group of nerds to fight the monsters and keep the town safe.