The Tangfani Pump House (Tangfani Oil Transfer Center), which was bombed several times during the Iran-Iraq War and then rebuilt, was once again targeted by Iraqi aircraft when it was opened and severely damaged. The National Oil Company officials believe that the only way to restart this important pump house, which is responsible for delivering crude oil to the country's three major refineries, is to move it underground. Specialists and workers, dressed as nomads, begin working underground, and Engineer Yeganeh is called to the area to direct the operation. In the meantime, several Iraqi regime spies, seeing the apparent halt in the reconstruction of the previous pump house, become suspicious of the movements and send one of their men to obtain information from Engineer Yeganeh through threats...