Karma

In a small village near the forest, the spritual leader lives a simple life and provides direction to the people when times are hard. He stays out of legal business and trys to get everyone to help their neighbors and be tolerant of peoples weaknesses.

Suddenly one day he is struck down by a high fever and delusions. Animals sicken and die one by one and children begin to carry a barking cough. The people begin to worry and tension rises. When you arrive in town, whether or not you were the priest they sent for, the townspeople are desperate for help. The spiritual leader has been babbling about ghosts walking among the living. The people what you to help.

Now the twist.

Once the cleric looks at the spiritual leader, any investigation will easily show that he is absolutely not possesed by spirits. Extensive probing can show that he is slowly being poisoned by a deadly herb that has been being slipped into everything he has been near. His soup and tea, even the water of his cold compress has the herb in it. If the animals are looked at, they have all been poisoned by yet another herb, and the children ar not in any great danger, but they have all been dosed with a herb that produces coughs.
If they check out all these occurances, they will make the obvious connection that a herbalist is bent on making the villagers lives hard. Problem is that there hasn't been a herbalist in the village for over twenty-five years since the spiritual leader had the last one burnt for a witch.
More investigation reveal that the spiritual leader's assistant was in contact with all of these things as well, but was only five when the witch was burnt and was to young to recieve any knowledge from the witch. If confronted, she may choose to reveal herself and more.
The assistant has been possesed by the so called witch. She has returned ofter the spiritual leader's former assistant died. They spiritual leader put the witch to death to keep her quiet about the fact he and his assistant had been involved with each other and she needed to abort a child. The assistant had only confided in her herbalist friend, who suddenly made the connection between spiritual leader and the assistant she had unwittingly poisoned. Now that she died without ever being a mother like the leader had always promised, the witch has come back in to the body of the spiritual leaders assistant's body to set up the whole town to believe that the spiritual leader is evil and life will only get better after he is gone. It's what he did to her after all.

Now the spirit can be left to take it's own path and kill the leader so the spirit can get some eternal rest, or the spirit could be banished, leaving only a dazed and confused girl to sort out her missing days, or the body could simply be hacked up to eliminate the creature from the world.