Astronaut Molly Woods tries to reconnect with her husband, John, and son, Ethan, after returning from a 13-month solo mission in outer space. Molly's mystifying experiences in space lead to events that will ultimately change the course of human history.

After Molly collapses and experiences a vision of her encounter on the Seraphim, Sam agrees to give her an ultrasound so she can learn more about her mysterious pregnancy. Also, Molly tracks down Kryger and he reveals the disturbing details of his own solo mission that the International Space Exploration Agency (ISEA) is keeping secret.

Molly has to decide if she is going to reveal her pregnancy to John after he confronts her about her distant behavior. Meanwhile, John and Molly face parents who are suspicious of Ethan when he goes to school for the first time.

After Sparks attempts to quarantine Molly, she and her family seek refuge on a remote island with her estranged father, Quinn. When the agency closes in on their whereabouts, Ethan is exposed to grave danger. Meanwhile, Yasumoto experiments with a strange and deadly substance.

When the validity of Molly's pregnancy comes into question, John begins to doubt her mental state. Meanwhile, Ethan suffers a serious setback, and John and Julie clash over how to care for him.

Molly finds footage that reveals the real reason she was chosen for the solo mission; Julie distracts herself with a mysterious man.