TES V: Skyrim Walkthrough (Master) - Part 228 - Darkfall Passage

Nedrustning and Serana now knows what they need to do in order to find Auriel's Bow, they must kill Knight-Paladin Gelebor's brother, who has been corrupted by the "betrayed", otherwise known as the Falmer, the twisted remnants of the Snow Elves, who were made that way due to generations of enslavement and manipulation of the Dwemer, so it's probably a good thing that they aren't still around as who knows what they'd do to other races! Anyway, the first wayshrine is somewhere beyond a large group of them...