President Richard Nixon's space race continues as NASA launches more Apollo missions to the moon while preparing for even greater projects, including a space station, a lunar base, and eventually an expedition to Mars. While Wendy Pendleton trains for her upcoming Apollo 23 mission, political forces are conspiring that might end that dream before it can be fulfilled. The Soviets, with dawning awareness of how the United States is leaving them behind in space, begin to take drastic measures to slow the Americans down.