悉尼发现自己面对面面对面与她失散多年的母亲，伊琳娜Derevko，其意图为女儿由冷竣清楚。然而，悉尼设法逃脱，并在台湾他们逃跑归队杰克和威尔。抵达洛杉矶后背上，悉尼继续她沃恩搜索，不知道他是否是由水在台北壁卷走后生死未卜。当他得知SD-6和悉尼的生活作为一个双重间谍的真相威尔的生活彻底改变了。此外，狄克逊必须决定是否通知悉尼的可疑活动斯隆。但杰克干预并且涵盖了悉尼谁后来发现沃恩谁帮助她试图追查她的母亲伊琳娜谁的灼热的称为Rimbaldi神器“圣经”。

　　Sydney finds herself face-to-face with her long-lost mother, Irina Derevko, whose intentions for her daughter are made chillingly clear. However, Sydney manages to escape and rejoin Jack and Will in their escape from Taiwan. After arriving back in Los Angeles, Sydney continues her search for Vaughn, not knowing if he is dead or alive after being swept away by a wall of water in Taipei. Will's life is forever changed when he learns the truth about SD-6 and Sydney's life as a double agent. Also, Dixon must decide whether or not to inform Sloane of Sydney's suspicious activities. But Jack intervenes and covers for Sydney who later finds Vaughn who helps her try to track down her mother Irina who's searing for a Rimbaldi artifact called 'the Bible.'