Hitchhiking on a deserted New Mexico road after his car breaks down, John Emmett (Sterling Hayden) gets picked up by Ann Nicholson (Ruth Roman), who is in a rush to reach Santa Fe, N.M. The distraught Ann is being pursued by psychiatrist Frederick Simmons (Werner Klemperer), who has been treating her in Los Angeles since she had a nervous breakdown, but she tells John that she is in possession of nuclear secrets that she must deliver to Dr. Reinhart Kissel (Karl Lindt) at a Santa Fe university.