With help from a confidential informant (a fellow Lida clone named M.K.) Beth Childs works to uncover a series of experiments orchestrated by Neolution -- all while her relationship with Paul falls apart. In the present-day, Sarah learns that her respite in Iceland is coming to an end.
Returning from her remote hideout Sarah discovers that Neolution has been implanting a mysterious and disturbing technology in the cheeks of its people. Cosima struggles with not knowing Delphine's fate, and a frustrated Felix sets out to find his biological family. Helena receives big news about her pregnancy.
Alison and Donnie decide to dig up the remains hidden in their garage to help the cause, only to see Helena cornered by a pair of homicide detectives. Felix reconnects with his biological sister, and Sarah searches for a way to remove the Neolution biotech. Elsewhere, Rachel receives a visit from the person behind her confinement.
Sarah strikes an alliance with Ferdinand to try and find Rachel, but finds Mika increasingly difficult to deal with. Donnie and Felix go undercover inside a fertility clinic that Beth once investigated, and Cosima and Scott get one of the Neolution implants under a microscope.
Cosima and Donnie go inside the Brightborn fertility clinic to uncover their true agenda, and Cosima comes face-to-face with her own creator -- while Donnie meets Krystal Goderitch, who is conducting her own investigation. Suspicious of Felix's new sister, Sarah decides to have them biologically tested.
Cosima and Sarah make plans to hand over the original genome to Neolution, in exchange for a cure for Cosima and the answers to the tech implanted in Sarah. After Detective Bell meets Krystal, Felix steps in to try and keep her out of the growing conflict.
Sarah returns to her old and reckless ways as she struggles with the consequences of her actions, leading her into the shadow of Beth's footsteps. Alison's attempt to create some normalcy with her daughter's birthday party is rudely interrupted, and with no options left Cosima makes a drastic decision.
After Donnie is threatened in prison Alison turns to her Neolution contact, putting her loyalties into question when her sisters discover her actions. Meanwhile Cosima negotiates with Susan Duncan to pursue a cure for Leda's shared ailment, and Mrs. S seeks vengeance.
Art and Sarah investigate an apparent suicide connected to Brightborn, while Cosima joins Susan Duncan on a remote island in an attempt to recreate the Leda genome. Felix tries to prevent Adele from learning too much about the clone club, but Helena's surprise return complicates things. Alison has a crisis of faith.
After a major discovery on the island communications with Cosima are cut off, leading the group to suspect a double-cross. Krystal demands full disclosure in exchange for information about Delphine, while a coup inside Brightborn could lead to a new beginning for human cloning.
