随着上一季的结束,Castor克隆人不再构成威胁,克隆人姐妹们的生活似乎可以回归平静,但孕育于过往的险境出现了:一个名为Neolution的组织一直在牵动Leda、Castor、Dyad 和 Topside的命运。在离开冰岛安全屋后,Sarah遇到了神秘的新盟友,而这个人与这一切的开端有着密不可分的联系——Beth Childs。在黑客 Dizzy 的帮助下,Sarah不得不跟随 Beth的脚步,慢慢走向强大的新敌人。Sarah的家人安全受到威胁,她承受着巨大的压力,与此同时,克隆人姐妹们正在被分开推往不同的方向。为了在这次考验中幸存下来,她们必须比此前任何时候都更团结一致。A flashback into the last several days in Beth's life acts as an extended prologue to the current day goings-on of the sisters. Beth has a source who she has not mentioned to anyone, including Art, which leads her and Art to their next case, what Art sees as just the homicide of a man named Edward Capra, but which Beth knows is part of what her source tells her is about the Neolutionists, who are all around her according to the source. As such, the source tells her not to trust anyone, even those closest to her. Two issues of interest concerning Capra are a square piece of his right cheek which has been removed, and reconstruction of his sex organ into two. Beth has to figure out how these two items relate to the Neolutionists. Beth has also just started managing the fund for her, Alison and Cosima, bankrolled by Alison for them to live while Beth largely shoulders the legwork on figuring out what is going on with them. She is dealing with all the stress in her life, which includes a s*** relationship with Paul, with cocaine use, and turning to the one person she figures she truly can trust for emotional comfort. But with Beth now gone, what were loose ends in her life start to reemerge for the living sisters...