Back to the Underworld - Ghost Girl Series, #1

After Kasey's transition from normal teen to part-time ghost, all she wanted to do was find a way to get back to a normal life. However, no matter what she tries-including risking the life of her best friend, Lindsey-she just can't seem to find any helpful information regarding her newfound abilities.  After one disastrous attempt at normalcy in which Lindsey drags Kasey to a Halloween party, Kasey begins to have even more trouble: she can't tell the dead from the living.
Searching for answers, she comes to find that those around her are not quite what they seem.