In the Hub, David Nash learns more from Anton about the World Ship, the citizens, and Olivia Sun. Meanwhile, a new piece of information may change everything...

Olivia Sun is introduced to a life she never knew, and her whole understanding of what she believed is called into question...

As refugees from the Frontier return to town, Flynn and Katherine work to feed those who have lost their supplies. Meanwhile, a contemplating John learns more about what it means to be "replaced" by the Core.

Olivia and Ronin finally arrive at an abandoned town, but what awaits in this unfamiliar territory is not what either of them could have ever expected...

More bad news arrives for the town council. As they seek alternative actions, many citizens begin to feel frustrated with the lack of leadership on the council's part...

Ronin and Olivia take their first steps into an abandoned World Ship with the hope of finding a way home...

Out in the void, away from the World Ship, three explorers find themselves further from home than they had ever dreamed possible...

After the loss of the latest Explorer mission, Elsie Lamarr and the citizens of the World Ship must deal with the fallout...