Your discovery in the Foundry caused Andras great alarm. Even the wild men of Dunland have tales of the Walking Shadows -- the Nazgûl, Ringwraiths under the domination of Sauron -- and he does not wish for such evil to come upon his people.
Andras has asked you to enter the tower of Orthanc and wrest Saruman's rings from him and dispose of them before the curse of the Nazgûl can fall upon any of his people.