I closed my eyes but couldn't sleep. It was very early morning and the cabin was completely silent...silent except for the most subtle, eerie sound. It was like water gently lapping against the shore, but the air was completely still. I trained my ears, wondering what it could be. It would go away for a minute, and then come back...but just barely, almost unnoticeable. I wondered if she could hear it too...my bedmate. She was the little sister of my best friend's wife, just turned 16. She had passed out hours ago and the space next to her was the only one left in the cabin.