This short but convoluted chain of quests starts at a Locked Cabinet upstairs in the house at Dalson's Tears in Western Plaguelands. There, you discover a locked cabinet, with no key. So, you start looking around for a key.
In the nearby barn, you find Mrs. Dalson's Diary. She describes that she locked her (newly undead) husband in the outhouse. ... and then belatedly remembered that he kept the key on him.
You slay the wandering skeleton (the mortal remains of Mrs Dalson, one would guess), and open the outhouse. Inside is a ghoul, the late, lamented Farmer Dalson.
This quest (or pair of quests) has often been reported as bugged. Whether these reports are due simply to not having followed all the steps described above, or whether they were actual bugs is unknown.