The town of Hamelin had a problem. Rats. Thousands and thousands of rats.

They were everywhere. They ate the grain in the barns. They chewed holes in the walls. They bit the cats and chased the dogs. They ran across the dinner table while families were trying to eat. The whole town was overrun.

The mayor and the town council tried everything. Traps, poison, cats — nothing worked. The rats just kept coming.

Then one day, a stranger came to town. He was tall and thin, dressed in a long coat of many colors — red and yellow and green — like a patchwork quilt. Under his arm, he carried a pipe.

"I can rid your town of every last rat," he said to the mayor. "But my price is one thousand gold coins."

"A thousand gold coins!" cried the mayor. He looked at the rats swarming through the streets. "Done. Get rid of the rats, and the gold is yours."

The stranger smiled. He lifted the pipe to his lips and began to play.

The music was strange and sweet — a thin, high melody that seemed to wind through every alley and under every door. And from every corner of the town, the rats came. They crept out of the walls. They poured out of the cellars. They streamed from the barns and the kitchens and the cupboards.

The piper walked slowly through the streets, playing his pipe, and every rat in Hamelin followed him. He led them out of the town gates, down the road, and into the river, where they were swept away by the current. Every last one.

The piper returned to the town square. "The rats are gone," he said. "Now, my thousand gold coins."

But the mayor looked around. The rats were gone. The streets were clean. And now that the problem was solved, one thousand gold coins seemed like an awful lot of money.

"One thousand? That's ridiculous," said the mayor. "I'll give you fifty."

The piper's eyes went cold. "You made a promise," he said quietly.

"Fifty coins," said the mayor. "Take it or leave it."

The piper said nothing. He turned and walked out of the town hall.

The next morning, the piper stood in the empty streets and lifted his pipe again. This time, the tune was different — lighter, sweeter, full of laughter and sunshine and faraway places.

And this time, it was not the rats who came. It was the children.

From every house, the children of Hamelin came running and skipping and dancing. They followed the piper through the streets, laughing as if they were going to the greatest party in the world.

The piper led them out of the town, up the road, and toward the mountains. A great door in the mountainside opened wide, and the children danced inside. The door closed behind them.

The people of Hamelin searched and called and wept, but their children were gone.

And the mayor learned, far too late, that a promise is a promise.