College professor and fly-fishing enthusiast Dr. James Boyd Houston is accused of harassing an attractive coed who is enrolled in one of his classes. The dean honors his one-year terminal contract but refuses to approve his application for tenure. He will be out of a job when the contract expires. Jimmy begins a halfhearted attempt to find other employment, but his primary task is to clear his name. State police trooper Peter Kowalski and lieutenant Sam Miller discover a young woman's body abandoned along a lonely stretch of West Virginia highway. Preliminary investigation reveals that she was driving a rental car from Philadelphia and had been shot in the head. The front of the car is speckled with tiny gossamer-winged mayflies. Lieutenant Miller, an aging police officer with an eye for detail, pieces together the woman's background and is surprised to discover evidence that leads him to the local college campus. The suspect is a well-respected botany professor. Jimmy is charged with the murder of his student. Out on bail, he uses his skills as a scientist and researcher to analyze the evidence against him. An uneasy truce is declared between Houston and Miller, who is not convinced of his guilt. Together they travel the mountains of West Virginia in search of the truth. Their investigation leads them through the dark worlds of devious friends, property developers, and drug dealers. As Dr. Houston experiences one catastrophe after another, he retreats to his ountain-top cabin. Unexpected help comes from the dean's administrative assistant, an attractive young woman who is willing to risk her job to help him. They discover a mutual attraction as they search for answers and explore the mountains they both so dearly love. As the mystery deepens, Jimmy is led from Laurel Mountain to Canaan Valley, Blackwater Falls, and Dolly Sods in his search for the truth.