介绍：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 out in Wittenberg endangers her relationship with Jack, and eventually she reveals the awful truth to Vaughn about her father having Irina murdered over a year earlier.

介绍：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 long dead; Marshall is having a baby with CIA tech expert Carrie Bowman; and Dixon is now the new division head of the L.A. office branch of the CIA. Sydney also learns the shocking fates of Jack and Sloane; the former is in CIA custody for communicating with Irina whom still is in hiding, while the latter is living in Switzerland under house arrest in exchange for co-operation with the CIA. Sydney is granted temporary CIA clearance on a case that may help her regain her memory and she meets a new enemy group called The Covenant.

介绍：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.