Nightschool: The Weirn Books

Synopsis

"Nightschool answers the age-old question — Where do demons get their diplomas?" The main setting of this series is at a building called the Nightschool. This is an ordinary high school during the day that transforms at sundown into a safe institution for Weirns, Vampires, Werewolves and other supernatural beings. The teachers conduct classes that teach a number of magic-based skills as well as common curricula (math, science, etc.) throughout the night. The main character of the series is a teenage girl named Alex, who is a weirn, a specific type of witch. She does not initially attend the Nightschool, for an unknown reason, and appears to be part of a mysterious prophecy. After her sister takes the night keeper post at the school and goes missing, Alex begins to wonder if the school had something to do with her disappearance. Alex enrolls as a new student to investigate and find her sister. (Source: Wikipedia)