When communication with Cosima is cut off and Neolution appears to be within striking distance, Sarah's alliance with Rachel goes out the window. Sarah lures a high-level Neolutionist into a trap, and sets out to bring down Neolution once and for all.

With Susan Duncan deposed, Sarah finds herself in the same position as Rachel–under Evie Cho's heel. The archenemies form an uneasy alliance in an attempt to bring Evie down and restore Susan to power.

As Alison is terrified by Neolution threats made against Donnie, Sarah and Mrs. S question her loyalty to her sestras. Siobhan sneaks out to seek vengeance. Cosima and Susan Duncan work together in a final attempt to discover a cure.

Sarah regresses to old habits while struggling to cope with a loss. Following in Beth's footsteps, Sarah questions her strength to carry on.

When Cosima admits doubts about finding a cure in time to save her life, Sarah makes a lone decision that exposes Kendall to those she's spent years hiding from. Meanwhile, Art and Felix team up to protect naïve clone, Krystal Goderitch, from herself.

While Sarah takes the day off to reconnect with Kira, Cosima steps up and infiltrates an exclusive Neolutionist fertility research center. A shocking discovery of their clandestine experiments leads her into a dangerous encounter.

Sarah forms an alliance with a former enemy in hopes of getting to the head of Neolution. Elsewhere: Alison orders Felix and Donnie to invade a Neolution fertility clinic and a Susan Duncan leaves Rachel to make a devastating decision.

As Sarah reels from the shocking discovery of Neolution's biotech, she's desperate to find answers. Always impulsive, she follows a lead into a harrowing encounter that requires the help of a reluctant new player. Eager to assist, Mrs. S strikes an alliance with an old nemesis. Rachel receives a visit from her keeper and takes a fraught step forward towards recovery. Meanwhile, Helena is mistaken for "Mrs. Hendrix" when she answers a visit from suspicious visitors.

After evading a Neolution attack in Iceland, Sarah returns home to track down an elusive new ally. She follows breadcrumbs and uncovers the next facet of Neolution's agenda – implanting dangerous technological devices in humans. However, those she left behind are wary about her return, not wanting to relinquish their semblance of normalcy. As Cosima struggles with Delphine's disappearance, Alison and Donnie host a pregnant and ever-hungry Helena. Meanwhile Felix, feeling like an outsider, embarks on his own journey of self-discovery.

After two months of respite, Sarah's hard-won refuge in Iceland is shattered by a Neolution attack. Once again forced to flee, she realizes no matter how far her family runs it will never be far enough.