Under the command of two experienced astronauts, a relatively untested crew set off on the Antares, a six year mission to seven planets in our solar system. The two senior astronauts, Maddux Donner and Ted Shaw, are a last minute substitute when those assigned to the mission are removed for medical reasons. Both had been on a mission to Mars 10 years before where they were forced to leave two of their party behind. Several others on the flight are also carrying personal baggage including Zoe Barnes, who is haunted by the sounds of a crying baby.

En route to Venus, the first of six planets to be visited on the mission, Zoe faces a deadly situation when she is testing a pressure suit and it begins to lose pressure. In flashbacks, we learn how Zoe dealt with the news she was pregnant and the identity of the father. Nadia wonders just why Steven is on the mission in the first place. From ground control, Eve Shaw tells he pilot husband Ted he has to go to Pod #4.

As instructed, Ted visits Pod 4 and is so disturbed by the experience that he is barely able to function. His wife Eve and one other person are the only ones to have been selected by the pod, as she explains it, and it is trying to communicate with him. He retreats to his room and provides little leadership, particularly when Donner determines there is a problem with the lander and he begins to suspect there is more going on than meets the eye. When Mission Control medical officer Claire Deroux discovers the crew is undergoing genetic changes, Eve reveals their well-kept secret. Having undergone various tests Ajay learns his fate.