Book IV: Chapter 1: Where is the Horse and the Rider?  

'Welcome to Imladris, (Player). It is good that you have come. Rest well, but not too deeply or too long! We have need of adventuring folk, for there is evil beyond the vale.

'Not more than two months ago, a hobbit by the name of Frodo Baggins and his companions were pursued to the Ford of Bruinen by servants of the Enemy. I speak of the Nine, the Nazgûl, fell creatures in the service of Sauron, and though the Bruinen fell upon them at my command, we have found the steeds of only eight. One of the Riders is unaccounted for.

'My sons set forth with scouts bound to them by friendship to seek this missing Rider. I ask that you speak with Elladan at their camp of Thorenhad, among the Bruinen Gorges, and lend your aid to the search. We must learn where this Nazgûl has gone, and most importantly, his designs.'

Servants of the Enemy pursued Frodo Baggins to the Bruinen, and though the hobbit and his friends were saved and the fell creatures defeated by the power of Elrond, not all of the Nazgûl have been accounted for.

Objective 1
Talk to Elladan

Elladan is at his camp of Thorenhad on the north-western slope of the Bruinen Gorges, north of the bear-dens.

Lord Elrond has asked you to lend your assistance to his sons Elladan and Elrohir, currently seeking the missing Nazgûl.