Certain Agony of the Battlefield – Paul is pushed into action when he discovers the ugly truth behind the Castor Boys’ logbooks of names. Meanwhile, Felix becomes desperate for information on Sarah’s whereabouts and presses the still-ailing Rachel for any shred of a lead.
By Means Which Have Never Yet Been Tried – 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.
Things Which Have Never Yet Been Done – Cosima takes a turn for the worse, which forces Sarah to take desperate measures that result in tragic consequences for those she loves. Meanwhile, the Proletheans set their ultimate plan in motion; and Alison and Donnie tangle with the law.
Variable and Full of Perturbation – A new player in the clone conspiracy emerges and turns up at Felix’s door, which sends him into crisis mode. Meanwhile, Sarah struggles with whether to surrender a crucial piece of leverage and strike a deal with Dyad.
Knowledge of Causes and Secret Motion of Things – A rehab confidante betrays Alison and threatens to expose the truth about Aynsley’s death, which causes Alison to go into a free fall on the eve of Family Day. The clones gather to contain the fallout.
To Hound Nature in Her Wanderings – 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.
Ipsa Scientia Potestas Est – 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.
Governed as It Were by Chance – 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.
Mingling Its Own Nature With It – Sarah turns to an old flame from her past as she hits the road with Felix, but their brief respite is brutally shattered. Sarah then realizes that no matter how far she runs it will never be far enough.