在第一季中,“黑色孤儿”Sarah在目击一次自杀时,偶然知道了自己的真实身份——她是一项前无古人的遗传学实验的成果,世界上还有很多和她一样的人。第二季,Sarah开始在一场绝命比赛中寻找失踪的女儿Kira。她的“焦土战术”引发了与支持克隆人的Rachel之间的对抗,这对所有和她一样的人来讲岌岌可危。一个精心打造的世界即将失控,Cosima的遗传病威胁着所有人。Sarah必须在极其危险的环境中与她的敌人谈判,以追查实验室的真相。随着Sarah更加了解自己的过去,新的神秘人出现了,但他们可以彼此信任吗?这个世界上,有无情的新玩家,正在争夺Sarah的命运操控权。Rachel has kidnapped Kira and Mrs. S. While trying to elude Rachel's thugs herself, Sarah has to decide whether to trust Paul as the person who has the best access to Rachel of those she knows in order to get Kira back. All Paul does tell Sarah is that there is a black tie event at Dyad at which Rachel will be in attendance. Sarah decides that she needs to attend the event - Cosima who already is an invitee - but has no plan beyond knowing that she will need to get in there with concealed gun in hand. With this scant outline of a plan, Sarah enlists the help of Felix and the other clones, although Sarah does end up enlisting their help also without their knowledge. Meanwhile, Cosima has decided to trust Delphine, Cosima's grand plan which is to take control of her own "biology" in dealing with her illness, as opposed to providing Leakie with this information. Alison wants her life to return as close to suburban normal as possible, which includes immersing herself into her community theater production, a possibly difficult task as the spirit of Aynsley hangs over the production. And Art and Angela are no longer officially working on the case as there is no case to work on, but they cannot let go of what little information they have on hand, especially as Art knows that Sarah was about to tell him everything just before she was sprung from jail.