Sidney Bristow is a college student who has an unusual job – she is a spy working for the CIA under secret conditions where not even her friends knows what she does. When her boyfriend proposes Sydney tells him what she does for a living and her employers kill him in line with procedures. Deciding to leave the agency before they kill her too Sydney discovers that she has actually been working for SD6, an agency that is actually a shadowy criminal organisation world-wide. Sydney joins the CIA and works as a double agent to help CIA Agent Vaughn to bring down SD6. She finds that her father is the other double agent within SD6 and the pair work together. While following her missions to uncover the work of the prophetic Rambaldi she must feed information back to the CIA without blowing her cover.

苏珊（梅丽莎·麦卡西 Melissa McCarthy 饰）是中情局专门协助处理危险任务却不为人知的后勤人员，她的搭档布莱德利（裘德·洛 Jude Law 饰）在一次行动中突然失踪，也波及另一位顶尖中情局特工瑞克（杰森·斯坦森 Jason Statham 饰 ）的安危。为了找出搭档的下落，拯救这个岌岌可危的世界，苏珊自愿充当卧底，混进史上最危险的军火商集团，试图查出事情的真相，并与蛇蝎美女头目（萝丝·拜恩 Rose Byrne 饰）斗智斗勇。然而在英勇救难的惊险过程中，苏珊发现事情远没有她想象的那么简单……

一位女间谍为捍卫国家，甘愿牺牲自身色相，最终还献出了宝贵的生命。

年轻美丽的雪梨.丝斯朵拥有两个截然不同的身份。表面上她是个大学研究所的学生，但实际身份却是SD－6情报员，雪梨以为她是在为国家工作，因为SD－6 …

西德妮-安妮-布里斯托是一个年轻充满活力的大学生，同时，也是神秘组织SD-6(CIA/中央情报局的最高秘密分支机构)的新生代情报员。几年后，当她将自己…

西德妮的母亲原是前苏联间谍，现 在则是某犯罪集团的首脑，一手掌握黑白两道许多人物的丑闻，在枪伤雪梨后以赎罪的心态向中情局投诚，并多次提供可以…

西德妮·布里斯托（Sidney Bristow）是一名大学生，她有一份不同寻常的工作——她是一名中情局（CIA）特工，工作处于保密状态，就连她的朋友们都不知道她的职业。当她的男友向她求婚时，西德妮向他坦白了自己的工作内容，结果她的上司按照规定将其男友杀害。西德妮决定在自己也惨遭毒手之前离开中情局，这时她却发现自己实际上……

五个月后，Sydney辞去了中情局（CIA）的工作，与Dixon、Jack、Vaughn以及Sloane一同加入了一个名为“授权人员专属”（Authorized Personnel Only，简称APO）的特别行动小组。为获得有限豁免权，Sloane选择与APO合作。与此同时，Sydney在维滕贝格（Wittenberg）发现的真相危及了她和Jack的关系，最终，她向Vaughn透露了那个可怕的真相：关于她父亲杀害Irina……

表面上，雪莉（珍妮弗·加纳 Jennifer Garner 饰）是一名普通的大学研究生，实际上，她已为名为SD6的秘密情报组织工作多年。在同男友结婚之际，雪莉决定向其公开自己的真实身份，没想到男友却因此被组织的安全人员暗杀。愤怒中，雪莉选择了“罢工”，之后亦遭到了抹杀。 危机之中，雪莉知道了自己的父亲杰克（维克托·加柏 Victor Garber 饰）也是和自己一样的秘密特工，并且，在背后扶持SD6的并非国家组织，而是拥有强大武力的反动分子。于私于公，雪莉和SD6都有着不共戴天之仇，她回到了SD6，但此时，雪莉的身份已升级成了为CIA工作的双重间谍，在危险和考验之中，雪莉的任务只有一个，那就是彻底铲除SD6。

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.'