I tread quietly up the plush carpeted stairs. There's no-one here to see me as Cassie and Jon's bedroom door creaks gently open. I've watched them from afar for so long. Now I'm finally in their house. But there's no time to waste. I'm here for a reason, and I'm going to get what I came for, whatever the cost... I open the front door and there's Amy, smiling sweetly and ready to help. She's been...