When Zo'or contracts an ancient deadly plague for which there is no known cure, Renee suggests to Liam that the virus could be used to create a biological weapon to fight the Taelons. She recruits Augur to research the virus and it's potential.

Liam is asked by a Church of the Companions member, Devon, to help find his girlfriend, also a member who has mysteriously disappeared. Sandoval gives Da'an some energy dust. Liam and Renee join the Church as homeless people. At the church's shelter they find that the food has a Taelon additive. In an underground environment on Church of the Companions land, Volunteers force drugged Church of the Companions members to harvest Kryss, a substance necessary that is vital to Taelons survival on Earth. Liam knows that Taelon plants only grow in 98F degree temperature. They discover that humans are being used to grow Kryss.

Lili Marquette gives birth to a half jaridian child, with the help of taelon core energy, that may be the last hope for the taelon and jaridian race. Auger goes into hiding from volunteer investigations, an old friend of his J Street agrees to help Liam and Renee while Auger is on the run. Sandoval tries to destroy evidence of the Jaridian existence.

The Taelons' fate - and possibly Liam's - is decided after Liam and Renee find Ma'el's regeneration chamber. The discovery of the secret location causes the surviving Taelons and Jaridians to seek the mechanism, which promises to restore their draining energy. Street, meanwhile, solves the riddle of Ma'el which will allow the Taelons and the Jaridians to join.