Unclean spirits - M. L. N. Hanover

The first novel in a bold and fast-paced new urban fantasy series starring Jayn? Heller, a young college student who inherits a string of houses across the world, several bank accounts, and a very unconventional business from her murdered uncle. And it turns out Uncle Eric has been fighting to rid the world of supernatural riders - demons, vampires, werewolves and all sorts of other nasty parasites - since before Jayn? was born.

Now it's up to Jayn? to avenge her uncle's death and continue his mission - if she can survive her first week on the job.