[3] Housewife Carol Turner accompanies her husband, Walter, on a business trip to Phoenix, which the two plan to conclude by driving back to their home in Denver.

When Walter's business obligation requires an extended stay, Carol arranges to drive back home herself, where her sister Vera is caring for the couple's two children, Nancy and Buddy.

Unable to reach Walter, Carol unsuccessfully attempts to book a flight, and later rents a station wagon to drive back to Denver.

The assailant — a serial killer with an electrolarynx — pursues Carol, but she manages to evade him by pulling off the interstate, where her station wagon finally dies on a remote country road.

Carol breaks into the station and manages to locate the pump keys in the register before being confronted by a vagrant who initially frightens her, but ultimately helps her retrieve gasoline.

At dawn, Carol again runs out of gas, and is directed by the elderly residents of a nearby home to a neighboring house several miles down the road, as the couple do not have a telephone, and their son, who is working on an irrigation ditch, has the keys to their truck.