One of my absolute favorite PotC fics, it's dark and occasionally disturbing. But I've loved it since the first time I read it, back when I had to print stories out at school to be able to read them. I've lost track of it twice now and been absolutely gutted.
Opportunity by Chrysanthemum and its sequel
Second Chances. I will admit, sadly, to not having found time to read the sequel yet, but the original. Just damn.