Alliances are shattered between Sarah and Rachel as Cosima is cut off from communication and the Neolution moves in. Later, Sarah sets a trap for a high-ranking Neolutionist in hopes of bring it down for good.moreless
With Evie Cho in charge of Neolution, Sarah finds herself in the same position as Rachel causing the archenemies to come together for the greater good. Cosima and Susan strongly disagree on the ethical implications of human experiments. When Adele further investigates Donnie’s case, she begins to suspect Felix is keeping deep secrets. Helena’s arrival forces Felix to make a difficult decision.moreless
Sarah and Mrs. S question Allison's loyalty when she becomes terrified by Neolution threats made against Donnie. With Sarah distracted, Siobhan sneaks out to seek vengeance. Cosima and Susan Duncan work together in one last attempt to discover a cure.moreless
Sarah goes back to old habits to cope with her decisions and Cosima attempts a Hail Mary back at the lab.
Cosima admits doubt about finding a cure, which causes Sarah to make a drastic decision that exposes Kendall to people she has been trying to hide from. Elsewhere, Art and Felix try to protect Krystal Goderitch from herself.moreless
Sarah has a sleuthing mission to discredit Felix's new ties after she tries reconnecting with Kira. Also, Cosima teams up with Donnie to further investigate the Neolutionist fertility research center.
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 Susan Duncan leaves Rachel to make a devastating decision.moreless
Sarah has a traumatic encounter as she investigates a shocking discovery of Neolution's biotech.
Sarah tracks down an elusive new ally and unearths the next aspect of the Neolution's agenda.
In the fourth season premiere, a Neolution attack destroys Sarah's refuge in Iceland and forces her to flee once again.
Castor and Topside force Sarah to make uncomfortable alliances. Donnie gives Helena an unexpected "gift" and the results of Alison’s candidacy finally come in. As team Leda takes a moment to breathe, change is in the works and a life hangs in the balance.moreless
Sarah, Felix and Mrs. S travel to London in hopes of finding the Castor Original but their enemies are not far behind. Donnie tries to save the family business when Pouchy absconds but it's Helena who manages to secure a "full refund". Cosmia is suspicious of Shay so Delphine attends to matters on her own. Everything will change when Leda finds what they've been looking for.moreless
Rachel agrees to decipher the secret code in Ethan's book but Sarah and the clone club will have to find a secret way out of Dyad for Rachel. Helena and Gracie work with Alison and Donnie at Bubbles. Donnie confronts Allison about Jason’s kiss and devises a plan to set Jason straight. Dr. Coady and Benchman scheme to track down the Castor Original. Rudy drops in on DYAD for a much needed asset. A new clone enters the picture.moreless
Alison must secure a store front in order to take their drug business to the “next level”. But Allison's her mother, Connie, proves to be a major hindrance. Felix helps Allison on her campaign for school trustee. Cosima, facing familiar health issues she thought she was over, calls on Alison for a favor. But it's Cosima who ends up doing a favor what with Alison trying to save Donnie from a heartless drug lord. Unassuming Scott gets closer to the greatest discovery of all when he sits down with Rachel to work on the secret key to decipher Ethan’s book, The Island of Dr Moreau.moreless
Paul finds the ugly truth behind the Castor Boys’ logbooks of names which pushes him into action. Felix is desperate for information on Sarah’s whereabouts so he pressures the still-ailing Rachel for any shred of a lead. In order for Donnie and Alison to take their money-making endeavor to the "next level" she must convince Jason Kellerman that her unique business plan will work.moreless
Sarah must step in to help when Mark is taken down in a Prolethean shoot-out. As Sarah collects intel putting her on the trail of the original Castor DNA, a familiar foe is not far behind. Helena continues to toil in a faraway military compound but it is ultimately Sarah’s fate that will hang in the balance as she tries to save her sister. Gracie is cast out from the Prolethean fold. Alison and Donnie come face-to-face with an unhappy drug lord.moreless
Leda and Castor are both on the hunt for original clone DNA. Mark and Gracie still on the lam pursue new leads to find the samples that might set them free, while Art and Sarah reunite to track them down. Cosima and Scott attempt to learn more about Castor’s biology. Alison’s new money-making venture is going gangbusters. A shocking revelation about the Castor-Leda connection leaves the sisters reeling, just before Sarah witnesses a deadly Prolethean-Castor face-off.moreless
Season 3 begins with Sarah pursuing the missing Helena who is being held in a faraway compound. Sarah uses her wiles and acting chops to deter a Topside investigator who threatens the Leda sisters' lives. Meanwhile, Cosima appears to be rebounding from her illness, while Alison and Donnie face newfound financial woes. When the menace of Castor rears its head once more, Sarah and her entire family must come together to survive.moreless
Season 2 ends with Sarah being forced to concede when Rachel launches her latest ploy. However, the Clone Club springs into action to save her. Later, Sarah meets a new ally and uncovers a terrifying new dimension to the conspiracy.moreless
Sarah becomes frantic when Cosima's health take a down turn, but her actions have heartbreaking costs for the others. The Proletheans implement their fundamental plan. Complications with the law involve Alison and Donnie.moreless
Sarah joins forces with an unlikely ally, when she follows a trail of clues that she hopes will lead her to the origins of the clone experiment. Meanwhile, Cosima and Delphine make a discovery that could prove to be the key to treating Cosima's illness.moreless
Rachel goes on the warpath and lashes out at Sarah's loved ones. While Sarah tries to keep them safe, an unexpected visitor threatens to derail her plans.
Sarah comes home to search for answers and with Cosima's help she digs into the origins of the clone experiment. The hunt takes her into perilous territory that could cost her more than she realizes.moreless
While Alison struggles with Aynsley's death and Cosima grapples with the worsening symptoms of her mysterious sickness, Sarah enlists Art's help to find Kira and is shocked when she learns where the trail leads.moreless
With Sarah out of options, she's on the run and being tracked by deadly adversaries. She suspects that pro-clone Rachel is behind the disappearance of Kira and ignites all out war against her. Allison sinks into guilt and depression after attending Aynsley's funeral. Cosima is confronted with a decision that could have calamitous results.moreless