Alison Dilaurentis is a new teacher starting at Rosewood High. She is 23 years old and only just moved into a house in a small wooded area which belongs to a friend of hers. Alison soon fits in to being the new teacher at school and meets lots of students but four certain students stand out, their names are Aria, Spencer, Hanna and Emily. She soon becomes close to them, but she also knows one of them. Where will this friendship take Alison?