[Nerwen]

Let's see... you mean like that one where Legolas' half-angel daughter got rescued by Glorfindel from a pack of random Orcs just outside the city of Rivendell? And then Elrond used his amazing healing powers on her? And she had an Irish male name? And Elladan fell in love with her? But it could never be because she was promised to another angel? And Legolas cried bitter tears as he recalled how his evil, angel-hating father had tried to kill his own granddaughter, leaving her with a terrible scar on her earlobe? And then Legolas turned out to have wings too, having turned into an angel himself due to being bitten by his angel wife? And then they went out carousing with the crew of the Elven pirate ship? And then Aragorn and Legolas had sex in a tree? And Mrs Legolas joined them to make a threesome? And then they got attacked by random Orcs again, and Legolas' daughter slaughtered heaps of them, but Legolas and Mrs Legolas were captured and tortured (Legolas had his wings cut off)? And Elladan comforted Legolas' daughter, falling even more deeply in love with her? And then the angel daughter's angel fiance showed up to be Elladan's rival? And then the writer deleted the story because nobody understood what a genius she was?

Yeah, that one. It was called "Complexity".