Why love when it destroys you?

When Sarah moves to a new place to run away from the memories of her old life and begin with a fresh start,she makes new friends and meets new guys. What if one of those guys start meaning more to her than she ever thought possible? But what about Nathan, her ex boyfriend, why is he back? Didn't he end it all? What does he want with her now?
What's up with her mom anyways? Where does she keep disappearing to every few days? Is she up to something? Does it involve Sarah?