Go in and follow the path to the ring building that branches off into three different directions. Follow the one that looks misty and spooky by heading generally in a straight line through it (be careful of the enemies in there, as they're hard to see and you can't lock onto them). You'll eventually come across the Shaded Ruins. From there, head straight and go up the stairs at the ends of the ruins to the area with the giant basilisk. Head right after disposing of the enemies that charge your way and you'll come to an area with two tower looking pillars. Follow the path that goes between them and you'll end up at Najka.

It's past the enemies, in that place, with the things.