“People been disappearing. Just them that are slow and sickly, for now. 'Course, they don't stop to cook their food like us. They just gnaw it into a few bloody clumps of hair and rags. Least that's all we find in the morning. I've even heard talk that there's some kind of giant rat god that tells 'em all what to do.”— Slim Picket
Feeding the dog near Klamath's town center a piece of meat jerky (he will cough a key up and follow the Chosen One around).
Bartering for the key (it has a value of 0, so he will accept anything offered.)
Once in the warrens, the Chosen One must battle their way down through the caves until they reach the second sub-floor. Below lies Keeng Ra'at the rat god, the brains behind the invasion. The giant rat has a considerable amount of HP, and will be challenging. If it gets a Critical Hit in the eyes, no matter the damage - it will always be fatal.
The following is based on unverified behind the scenes information and has not been confirmed by canon sources.
When the quest is completed and the Chosen One talks to Slim afterwards, he will state how they are a regular "Pied Piper". In accordance to the goal of this quest, the 'Pied Piper' is a mythical character said to have removed an infestation of rats from the town of Hamelin during the Middle Ages.
End of information based on unverified behind the scenes information.