The emissary from Isengard that Lheu Brenin has imprisoned is not doing well, and the leader of the Falcon-clan wants you to try and learn something of Saruman's plans before the captive dies.
'I thought that the captive might tell us more about Saruman's plans if he was hungrier. I told Nai to stop feeding him, but now he has taken ill and will not last much longer.
'Come with me to speak with him before he dies. There will be no more chances to learn what the Wizard is up to behind his walls before it comes to open war.
'We will give him a meal if he cooperates. That may be the encouragement he needs.'
Lheu Brenin is outside his home in Tûr Morva.
Lheu Brenin has asked you to come with him to speak with his captive.
If you left the Isengard Depths without the Reminder of Captivity in your inventory, go to the cart just to the right of the gate of Isengard and use it to return to the Depths.
You have been taken prisoner and brought to Isengard. The Falcon-clan has betrayed you, and you are now the prisoner of Saruman.