As Alison is terrified by Neolution threats made against Donnie, Sarah and Mrs. S question her loyalty to her sisters. While Sarah is distracted, Siobhan sneaks out to seek vengeance. Meanwhile, Cosima and Susan Duncan work together in a final attempt to discover a cure.
Elenco: Tatiana Maslany , Dylan Bruce , Jordan Gavaris , Kristian Bruun , Kevin Hanchard , Maria Doyle Kennedy , Évelyne Brochu , Incorrect Aspect Ratio , Inga Cadranel , Kevin Hanchard , Kristian Bruun , Maria Doyle Kennedy , Matt Frewer , Michael Mando , Michiel Huisman , Millie Davis , Natalie Lisinska , Peter Outerbridge , Ron Lea , Skyler Wexler , زينة .