What is the plot line or story map for Wanted by Sara Shepard?

The plot line is that Ms.DiLaurentis drops a bomb on Rosewood saying that Ali had a twin named Courtney.And Spencer Hanna Aria and Emily become friends with Courtney.Except there friendship with Courtney is better than what they had with Ali.BUt turns out that Courtney was the real one dead,Ali killed her.And Ali was the one that Ms.DiLaurentis introduced to everybody.Then Ali(the real one) tried to kill them but failed and I'm sure she died in the fire instead.
Bonus: Ali killed Ian,Jenna and Courtney.And Ali was the second A.