The Stones of Peril — James C. Work

It's the 1920s. Ranger Tim McIntyre's job is to protect the new Rocky Mountain National Park and see that visitors have a good time. But two visitors are found dead -- one hanged, perhaps by accident, one poisoned, less likely by accident -- and two small, cloaked figures have been seen adding new rocks to Flattop Mountain's ancient stone medicine circle. And who's this woman who is running around clad only in a leopard skin, telling people she's the New Eve of the 1920s? At least the ranger will have help untangling the puzzles -- his glamorous friend, Vi Coteau, informs him that she's coming from Denver to go backcountry camping with him while he looks for the source of the rocks. Whether he likes it or not.