Jardek Anton, Baron of Threehills, is dead. His will has not yet been opened, because the one person indicated by the Baron as his executor has not been found. This person, unknown to any of those close to the late Baron, must be found before the will can be opened and read, before any of his loyal retainers can discover how they have been rewarded. This person, of course, is a party member, unaware that he or she has a wealthy uncle, Uncle Jardek, and equally unaware that this unknown uncle has nefarious plans that will reach from beyond the grave!
If thunder shook your house as you read that last line, so much the better.
For 4th - 6th level characters