James Wolk扮演年轻叛逆的美国动物学家Jackson Oz，常年在非洲生活，担任游客的旅行向导。当他在非洲的荒野之中旅行时，发现动物们表现出奇怪的攻击行为。很快，动物们的攻击行为变得更可怕、更狡猾、更有组织。他联想起父亲在临终前所说的那个颇具争议的理论：动物可能威胁人类的生存。父亲的理论与他亲眼所见的事实存在某种关联性，他有理由怀疑整件事背后隐藏着一个巨大的阴谋。他必须尽快解开这种奇怪症状大流行的真正原因否则人类很快将无处躲藏。
Five months later. Sydney quits the CIA and joins a Black Ops unit called "Authorized Personnel Only" alongside Dixon, Jack, Vaughn and... Sloane whom for limited immunity is co-operating with the APO. Meanwhile, the truth Sydney found o
Having woken up in Hong Kong, with no memory for the last two years (!), Sydney returns to Los Angeles to try to piece together the last two years of her life and discovers the fates of her friends and family: Vaughn has married thinking that Sydney was l
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 Ang
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，
