Unfortunate Accidents :

Cousins Margo and Cassandra Crowfeather have no idea of the trouble they’ve stepped into at the beginning of the school year. The school has been overtaken by demons! And these demons are here to teach the students a new way to think. The most promising students are rewarded with a special surgery at the new clinic that just opened downtown. A surgery that changes them in both body and soul. Now these evil creatures have singled out both Margo and Cassandra for the special treatment!