Six months after an alien artifact lands on the earth, Niko Breckinridge leads a crew on a mission into deep space to try and find who sent it. Back home, her husband Erik studies the artifact and the signal it is transmitting.
The crew of the Salvare lands on a rogue planet in search of oxygen, despite tensions that continue to call Niko's leadership into question. Back on Earth, Erik is approached by Harper Glass when she learns that contact with the ship has been lost.
Trapped in her soma pod, Niko moves from one possible world to the next as she dreams of what her life -- and the fate of her two crews -- might have been.
The discovery of another of the alien artifacts on the surface of a moon brings the Salvare crew to investigate. Meanwhile Erik and Harper hope that her followers can help to solve the mystery of the artifact on Earth.
Niko attempts to effect repairs outside the ship after a glitch puts William offline, but risks being left stranded in deep space. Cas and Niko try to deal with their personal issues, and Sasha turns to meditation to get rid of the voice in his head.
Erik's project has a major breakthrough with the alien artifact on Earth, prompting a trip inside and a strange encounter with members of the Salvare crew -- while on the ship Sasha runs recon for someone else.
While the Salvare navigates a dark matter nebula without light, the crew begins to exhibit strange behavioral symptoms. Erik rushes Jana to the hospital, and William struggles over his feelings for Niko.
Sasha separates the crew from one another while attempting to destroy the Salvare. Bernie puts his life on the line to save the particle accelerator, while back on Earth Erik questions Harper -- whose mind has apparently been taken over by an alien parasite.
When the Salvare reaches what they think is the Achaia homeworld, Niko leads a mission to the surface to attempt to learn more about the alien race and its intentions. With his daughter's life on the line, Erik faces a difficult choice.
