An angel of death

Ashliel and her brother have been hunters of the supernatural since there parents died, now they have to go to an old school and infiltrate it, and purge it of vampires. The catch though, the school is made for the vampires, with few humans.. and how are you supposed to do your job, when the school is old fashioned and another family has a hunter there, one the Herondale family despises, then what happens when this warrior is an angel with a cold heart, finds love in another? all the while a war is happening, and your the center of it, on top of it you must abandon the school.