When Sydney gets bitten on the neck by a missing in action CIA agent, she soon finds out that she has been infected by a experiential hallucinogen, causing her to slowly ...

Sydney and Vaughn go undercover as an arms dealing married couple in a mock-up setting of American suburbia to find a stolen electro-magnetic pulse weapon that when deton ...

Sydney and Vaughn go undercover to track down a deadly new bio-weapon. Meanwhile, Sydney is concerned about Vaughn not having yet put Lauren behind, and Nadia turns to a ...

Sydney must seduce Martin Bishop, a murderous arms dealer in order to track down a stolen NSA code-breaker. Meanwhile, Vaughn fears for Weiss's life, and Sydney and Jack ...

Sydney unwillingly teams up with her father to hunt down a modern-day samurai, named Kazu Tamazaki. Meanwhile, Nadia is back home in Argentina and refuses to go back into ...

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 ...

Lauren stages a stunning betrayal by impersonating Sydney and blowing up the CIA offices to steal classified materials, and nearly killing Marshall in the process. But Sa ...

With the aid of Katya Derevko and CIA imprisoned security systems designer Toni Cummings, Sydney and Vaughn attempt to track down Sloane and Nadia. But Lauren and Sark ar ...

After finally discovering the identity of the Rambaldi Passenger, who is Sloane's illegitimate daughter, Sydney and Jack seek the aid of Sloane, to track the Passenger do ...

After finding out that Lauren really is working for the Covenant, Vaughn is told by Jack and Sydney to keep up the facade of a happy marriage in order to keep tabs on his ...

Sydney and Jack warn a disbelieving Vaughn about their suspicions of Lauren being the CIA mole. Meanwhile, Kazari Bomani and Sark take possession of the Rambaldi machine ...

Sydney and Vaughn must track Kazari Bomani down to get hold of a piece of the Rambaldi puzzle before the Covenant gets their hands on it. Meanwhile, Jack reveals his susp ...

Sydney attempts to rescue Dixon's kids after they are kidnapped by Sark. Meanwhile, Lauren's status as a double agent for the CIA and the Covenant is put to the test when ...

Sydney and Vaughn must convince bomb maker Daniel Ryan that they are part of The Covenant in order to find out where he has hidden one of his devices. But Sydney discover ...

While trying to retrieve a bomb, Sydney and Vaughn are ambushed by unidentified assailants. Meanwhile, Lauren and Sark continue to solidify their new partnership as the n ...

Sydney and Vaughn are sent to retrieve the Doleac Agenda to gain an advantage over The Covenant. For this, Sydney and Weiss must convince rogue security systems designer ...

Jack contacts a mysterious woman, that of former KGB agent Katya Derevko, Irina's older sister, to help him free Sydney and Vaughn, whose plane has crashed inside North K ...

In this episode, Sydney finally learns the shocking truth about her missing two years from an unlikely source: FBI Special Officer Kendall. Kendall whisks her away and ta ...

The identity of the mysterious St. Aidan forces Sydney to pull a stunned Will Tippin out of witness protection for help in finding Lazarey to clear her name. But the purs ...

After making a shocking discovery of a severed human hand in the desert that belonged to Lazarey, the Russian diplomat she murdered while working as a brainwashed assassi ...

When Sydney is taken into custody by the NSC honcho Mr. Lindsey, Jack and Vaughn have no choice but to ally themselves with Sloane to rescue her. But with only hours to s ...

Jack takes drastic measures to ensure that the NSC never finds out the truth about Sydney's murder of the Russian diplomat Lazarey. But, his actions place a heavy strain ...

Sydney's emotions are turned inside-out when she once again comes face-to-face with Allison Doren, the murdered Francie's doppelgänger, who was presumed dead but is now ...

While Vaughn's life hangs in the balance, Lauren butts heads with Sydney after learning the part she played in his stabbing. Meanwhile, Sydney further questions Sloane's ...

Sydney discovers a link to her missing two years in the form of Simon Walker, the dangerous leader of a group determined on retrieving deadly biological weapons. Meanwhil ...

Sydney and Vaughn are reunited again as a team to prevent Sark, now a head leader of the Covenant, from destroying the nation's satellite communications system. Meanwhile ...

Sydney's search for her past leads to an imprisoned Sark, but their QandA is cut short when he becomes the ransom for a pair of abducted CIA scientists by the Covenant, w ...

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 discove ...

Sydney Bristow is a young, athletic, college graduate who was recruited her freshman year as a Secret Agent for SD-6, a top-secret branch of the C.I.A. After a few years, ...

Sydney must confront her mother, who tells a clue about some Rambaldi artefacts in Zurich, but it was a trap to capture Jack. As Sloane keeps the latter in hostage, Vaugh ...

Sydney finds herself racing to clear Will's name when the Francie impostor frames him for the CIA intelligent leak by making him appear to be the other double of the Heli ...

Dixon struggles to deal with the death of his wife but returns to work after only four days, hellbent on tracking down Arvin Sloane. Vaughn questions his ability to cope ...