Little Town of Hamlin
Rats were not the real problem in Hamlin. It was zombies. They roamed the streets¸ attacking peasants¸ assaulting the stockades and even threatening nobles...
Until the Piper came to town. Just as the largest force of zombies Hamlin had ever seen began breaking through the barricades¸ the Piper arrived and somehow led them away. All he asked at the time was a bit of gold.
When the Piper returned for payment¸ the Mayor sent him away empty handed.