The Mystery of the Diamond Triangle - S1.E4

After Nancy and her girlfriend, George, see an automobile run off the road. Nancy tells her boyfriend, Ned Nickerson, to report it to the sheriff. Later the sheriff tells Nancy that his men could not find any signs of an accident, and that the road has been closed for a long time. Nancy attempts to unravel the bizarre occurrence on her own, and soon finds herself in the midst of danger.