Alex and Abby- Their Story

Twins Alexander (Alex) and Abigail (Abby) along with there friends go on a trip to Las Vegas and California. While in Vegas something happens to Abby, that she thinks is just a dream. But it turns out not to be. She tries to run from it but it seems to follow her. What exactly happened that night in Vegas, and why wont it go away? Must read to find out what is going on