Audiobook: Outdoor Girls Around the Campfire

This is book #13 in the "Outdoor Girls" series.

The girls decide to camp out at a shack along the shores of Rainbow Lake, but when they arrive it has burned to the ground. Who is prowling around the camp at night, and what is the story of a sweet old lady they meet, known as the Old Maid of the Mountains. (Summary by Maria Therese)