Worlds Colliding (Pretty Little Liars) Book One

It has been a year since Alison DiLaurentis has disappeared, leaving her friends and her family in her wake, in their grief and confusion.
The five best friends, Aria Montgomery, Spencer Hastings, Hanna Marin, Emily Fields and Dakota McCoy are getting weird texts from a mysterious person called "A", who is forcing them to do things they want to do in order to keep their secrets and their families safe.
Alison's sister Penelope "Pen" DiLaurentis has dealt with these texts from the same person right before Ali had disappeared. And now, after they find a body that they think is Alison's, Pen has been getting the texts again. They unnerve her and scare her to no end, which doesn't go unnoticed by her best friends, Lucy Fields, Peyton Hastings, and Madison Marin. These four girls had become friends since their older sister had made a gateway because of their friendship led the families to spending so much time together.
And Evan Montgomery, brother to Aria and Mike, along with all of these characters, are going to deal with their separate issues, family, business, school, or personal.
Can they make it through this?
Or will the secrets destroy them all?