The Drowning Series by Rachel Ward

What happens if you've done something terrible? But you can't remember what. And you don't know how to put it right ...When Carl opens his eyes on the banks of a lake, his brother is being zipped into a body bag. What happened in the water? He can't remember And when he glimpses a beautiful girl he thinks he recognizes, she runs away. Suddenly he knows he must find her - because together they must face the truth before it drowns them.