简介：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. 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 是个属于中央情报局的秘密分支机构。但是雪梨并不了解事情的真相，在接受男友意外求婚后，雪梨决定两人之间应该完全坦白，于是向他吐露出自己情报员的身份，不料，这项突来的告白，却为男友带来了杀身之祸，雪梨在向SD-6的长官求证后，发现男友正是死在SD-6的手下，雪梨的长官告诉她，这一切都是她自己的错，因为她犯下了情报员的大忌——暴露身份……
