A Happening in Hamelin (1969)

Franz leaves his family behind in their humble abode in the mountains and goes in search of fortune, equipped only with his inseparable guitar on his back. He stumbles upon Buna, a sorcerer who helps him attain success and notoriety in a town called Hamelin. Franz is hired by the mayor to rid the town of a plague of rats. He leads away the town's rodents, and children, with his music in this rock and roll adaptation of The Pied Piper of Hamelin.