The Missing Prince is a main quest in The Elder Scrolls II: Daggerfall, in which Prince Lhotun wishes to learn the fate of his brother. He sends the player off to find out more. During the quest, an agent of the Underking is encountered in order to discredit the rumors that the Underking was involved in the prince going missing. This agent says the following:
"Agent (Player name)? Shhh. I would prefer that nobody sees me talking with you. It has come to our attention that the Underking is being wrongly accused of abducting prince Arthago (Or another name). Before you judge, check into Castle Faallem (A random ruin). I'll mark it on your map. Who am I? Just call me a loyal servant. Now move away before anyone gets suspicious. Go on, scram."
With the location provided through the agent of the Underking, a Death Certificate can be found, which is the evidence needed to inform Lhotun of the fate of his brother.