When Chase hears a desperate late-night call for help from his shortwave radio, strange happenings are soon in store for the Bon Air Boys. As the people of Lewisville begin to help stranded passengers of a crippled train, a suspicious stranger hides in the shadows. When Frank, Griff, and Chase find a peculiar key, the search begins for the missing railroad payroll. Before long three different mysteries unfold, and Sheriff Jenkins calls on the band of best friends to help solve the exciting and satisfying "whodunit" case found in the third book in the Bon Air Boys Adventure Series.