The pied piper of hamelin

The Piper heads out into the street and again begins to play his flute. However, this time it is not rats, but the children of the town who begin to follow him. The adults find themselves unable to move as they watch the children dancing along behind the Piper as he heads out of town. Finally, the adults are able to move and decide to follow at a distance, assuming he will sooner or later have to stop playing. But when the Piper reaches a nearby mountain, a magic portal opens and all the children disappear with him into it. The speaker then tells of one boy, whose lame foot prohibited him from keeping up and who was thus left behind. He remains sad and distraught the rest of his days for not having glimpsed whatever promise lay in the Piper's song.