Uninvited - Amanda Marrone

Jordan hates her life! Her boyfriend Michael dumped her, hooked up with half the other girls in the neighbourhood, and then killed himself. And then there's the broken record of boring parties, meaningless flirting and friends she can't relate to. But now, somehow, Michael is back, appearing at her window every night, begging her to let him in.
Jordan can't understand why he wants to get back together; he was the one that dumped her! But, as the weeks drag on, she feels her resistance wearing down. Instead of partying and socialising with her so-called friends, now Jordan runs home to the safety of her room before dark, and waits, alone and terrified, for the sun to go down.
Creatures like Michael need to be invited in before they can cross over the threshold. All Jordan has to do is say the words…