I'm kind of reminded of the wizard of oz, where Dorothy's house is picked up and dropped near the yellow brick road by a tornado. On top of a witch no less, so maybe the hag can make her way into the story that way. Then one of the locals could ask if someone in the adventuring party "was a good hag or a bad hag."

It would be pretty easy to just copy the wizard of oz wholesale and just edit parts to make them feel more like a D&D campaign. Though there are a few stories that feature people getting spirited away for one reason or another.