In a Mexican town along the U.S.–Mexico border, a time bomb is planted in a car. Rudy Linnekar (Jeffrey Green) and Zita (Joi Lansing) enter the vehicle and make a slow journey through town to the U.S. border, during which Zita insists that she can hear something ticking. Newlyweds Miguel "Mike" Vargas (Charlton Heston), a drug enforcement official in the Mexican government, and his wife Susie (Janet Leigh) pass the car several times on foot. The car crosses the border, then explodes.