After Earth is rendered uninhabitable, Androids Mother and Father start a new settlement and family with human embryos on the planet Kepler-22b. Twelve years later, only one child, Campion, remains, and the arrival of an Ark of surviving humans called the Mithraic presents a threat that Mother has no choice but to confront.

After a confrontation with Marcus, Mother discovers and takes five Mithraic children (Hunter, Tempest, Paul, Holly and Vita) back to her settlement. While Mother, Father and Campion, adjust to living with a new group of Earth-born children, Marcus struggles to survive alone on Kepler-22b.

After the Mithraic kids fall sick, Campion believes Mother is poisoning them and plans an escape. As Mother and Father attempt to prove otherwise, Marcus and Sue work to convince the other surviving Mithraic to mount a rescue of the children, desperate to get their son Paul back.

Father tries to teach the children how to hunt some of Kepler-22b’s mysterious creatures for food. Meanwhile, the Mithraic make a stunning discovery that potentially fulfills a Mithraic prophecy, and a debate about how to proceed ignites a conflict between Marcus and the Mithraic leader, Ambrose.

Marcus moves forward with a plan to rescue the Mithraic children, but first he has to find them. Back at the settlement, Campion and Paul bond while on a hunting expedition with Father, and Mother attempts to learn more about her origins.

After rekindling her connection to her creator, Mother finds herself distracted by intense feelings she didn’t know she was capable of having, unaware that Marcus, Sue and the Mithraic are closing in on the settlement.

Marcus’s decisions stress his relationship to his family as he struggles to maintain his clout as leader of the Mithraic. Mother is able to see Marcus for who he truly is, which threatens his power and puts Mother in a precarious situation she might not recover from. Meanwhile, Campion is faced with a choice that could result in dire consequences.

As Marcus continues to embrace his Mithraic devotion, Sue worries he may no longer have her and Paul’s best interests at heart. Meanwhile, Mother experiences what she believes to be malfunctions, and Hunter works on a secret project with Father.

Sue is determined to keep the children safe, and in doing so, struggles with whether or not she can trust Mother. Meanwhile, a new threat arises and an increasingly erratic Marcus causes the Mithraic to question their leader.

Paul begins displaying troubling behavior not unlike that of Marcus, leading to a shocking discovery. Father struggles with human-like emotions. Mother and Father discover a startling secret about the planet they’re on, just as a new threat arrives on Kepler-22b.

While Mother, Father, and the children face hostility from their new atheist collective, Marcus sets out to fill the walls of an ancient church with Sol’s worshippers.

While the collective is tasked with hunting down the serpent, Mother is left to reconcile complicated emotions. Convinced that it will aid his cause, Marcus sets out to find the creature before the atheists do.

Using his mysterious new powers, Marcus rescues a group of Mithraic prisoners, while Mother discovers the serpent is not a maneater but an herbivore. Father works through his frustration over Mother’s decision to spare the serpent’s life by engrossing himself in his work project, the regeneration of an ancient android.

After the Trust uses Paul to strike back against Marcus, Mother confronts the Trust and threatens a coup. Meanwhile, on the run from Mother, Marcus has to keep his followers from losing faith as his powers suddenly disappear.

Mother struggles to keep the collective from falling apart as she struggles to lead while Sue resorts to prayer in her desperation to cure Paul. Meanwhile, Marcus and his followers are given new hope as they discover an ancient temple. But as Marcus investigates the temple’s secrets, Decima and the rest of his followers are made to answer for their sins.

As they try and fail to open the seed box, Sue and Paul realize they need Marcus’s help. Sue makes a plan to break Marcus out of the brig while Mother is distracted with the imminent birth of Tempest’s baby. But when Sue, Paul and Marcus finally open the seed box, they make a horrifying discovery.

A reeling Marcus and Paul join forces with Mother to disarm the newly weaponized serpent before it wreaks unimaginable havoc.

Grandmother reveals her own agenda, Marcus seeks revenge, and Mother sets out to neutralize the serpent – but is leveled by the fallout.