Rocky Mountain National Park Ranger Tim McIntyre is torn away from fantasies about how much fly-fishing he can fit into his vacation when he's roped into using his free time for an informal investigation as a favor to his "friend" 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. Well, 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 buried treasure known as "The Dunraven Hoard." One of the boys has died during the exploration, and the other two are the most likely suspects if the death is murder rather than misadventure. Richard's father, William, asks McIntyre and Vi to investigate, if only to keep his son in the clear. McIntyre ponders motive and opportunity as the college boys are cut down one by one, though he'd probably solve the mystery faster if he spent more time tracking the killer and less time considering how Vi handles her gun...