When a treasure hunt at a Colorado mine turns deadly for some college students in the 1920s, a park ranger works with a lady friend who's employed by the FBI to suss out the root of the trouble.
With a two-week vacation so close he can feel it, Rocky Mountain National Park Ranger Timothy Grayson McIntyre is torn away from fantasies about how much fly-fishing he can fit in when he's roped into using his free time for an informal investigation as a favor to a friend. That's fine with McIntyre, because the friend is FBI secretary Vi Coteau, and investigating at his sweetheart's behest makes it likely that he'll be spending time in close quarters with her. And no quarters could be closer than exploring Colorado's labyrinthine mines, where upper-crust undergraduate Richard Leup and two fraternity brothers have been exploring in search of that well-known buried treasure, the Dunraven Hoard. One of the boys has been killed during the explorations, and the other two seem the most likely suspects if the death turns out to be murder and not misadventure. Richard's father, William, a friend of Vi's, asks McIntyre and Vi to investigate, if only to keep Richard in the clear, though McIntyre needs no excuse to spend time with Vi outside the confines of her society set. McIntyre ponders motive and opportunity in putting together the pieces of the puzzle as the college boys, who've been given little individual personality of their own, are cut down one by one. He doesn't seem to realize that he'd probably solve the mystery faster if he spent more time tracking the killer and less considering where Vi stores her gun.
This sturdy homage to 1920s national parks lacks the oomph that would make it memorable.