#304 - A Missing Link (Guest starring Justin Theroux)
Sydney accepts a deed cover assignment to stop Sark and The Covenant from acquiring biological weapons. However, when she encounters the mercenary group tasked to steal the virus, Syd discovers a link to her missing time. Meanwhile, Jack decides it's time to reveal the identity of Lazarey's murderer.
Original US Airdate: 19th October, 2003

#305 - Repercussions (Guest starring Justin Theroux and Djimon Hounsou)
As Vaughn's life hangs in the balance, Sydney butts heads with Lauren Reed (his wife) who wants to transfer Syd to another field office. Meanwhile, Arvin Sloane is kidnapped by Covenant kingpin Kazari Bomani who wants to make him a double agent and Jack goes after Simon Walker before he goes underground.
Original US Airdate: 26th October, 2003

#306 - Nemesis (Guest starring Merrin Dungey)
Allison Doren, the helix double who killed Francie, resurfaces and provides another lead to Sydney's missing time. However, the situation is further complicated when the CIA assigns Syd as Sloane's handler in his dealings with the Covenant. Meanwhile, Lauren becomes one step closer to identifying Lazarey's murderer.
Original US Airdate: 2nd November, 2003

#307 - Prelude
Lauren finally discovers the truth, and quickly informs the National Security Council that it was Sydney who murdered Lazarey. At the same time, Sloane gives Sydney a key he received the day before the returned from the grave...a key she sent to him. Meanwhile, Vaughn and Jack debate the importance of protecting Syd's secret.
Original US Airdate: 9th November, 2003

#308 - Breaking Point (Guest starring Richard Roundtree)
Being held in NSC custody, Sydney is tortured for information regarding her missing two years and NSC Director Robert Lindsey orders the invasive surgery to retore her memory...a treatment which could do more harm than good. To save her, Jack enlists his old-school CIA contacts in order to mount a rescue party.
Original US Airdate: 16th November, 2003

#309 - Conscious (Guest starring David Cronenberg)
Sloane identifies a doctor who might have a radical treatment that will help Sydney recover her memories. Meanwhile, it is up to Lauren Reed to convince the NSC that it was the Covenant who abducted Sydney from their facility. Lindsey goes to Sloane for confirmation, who in turn offers an exchange - Sydney Bristow for his Rambaldi device.
Original US Airdate: 30th November, 2003

#310 - Remnants (Guest starring Bradley Cooper and Merrin Dungey)
Will Tippin might be the key to Sydney's lost memories, forcing her to break him out of Witness Protection in order to track down one of his mysterious contacts - a man known only as St. Aiden. Meanwhile, Lindsey asks Sloane to make arrangements for Sydney's assasination and Sark attempts to find a Rambaldi artifact.
Original US Airdate: 7th December, 2003

#311 - Full Disclosure (Guest starring Terry O'Quinn)
Director Kendall flies Sydney to a DSR facility in order to share with her the truth about her missing time - she was working undercover for the Department of Special Research in order to track down a Rambaldi object that could bring about the end of the world. The same object that she and Will recovered from Switzerland and later stolen from the CIA.
Original US Airdate: 11th January, 2004

#312 - Crossings (Guest starring Isabella Rossellini)
When a plane carrying Vaughn and Syd is shot down over a province in North Korea, the two agents are stranded and eventually come face to face with a firing squad. To save them, Jack sends a message to his ex-wife Irina Derevko who sends someone to help...her sister Katya, Sydney's aunt.
Original US Airdate: 18th January, 2004

#313 - After Six (Guest starring Quentin Tarantino and Vivica Fox)
Weiss and Sydney go on a mission to gain intel on a fortified Covenant facility so they can carry out a raid on all of the organisations higher-placed assets. However, Sark and Lauren have an agenda of their own when they start killing off the leaders of the terrorist group in order to push themselves into a higher position.
Original US Airdate: 15th February, 2004

#314 - Blowback
The CIA goes after a new weapon being developed that is more powerful than any standard explosive device. During the mission however, Sydney and Vaughn are continuously thwarted by two Covenant agents - Lauren and Sark. Meanwhile, Sloane continues to speak with Doctor Barnett regarding his terrible secret.
Original US Airdate: 7th March, 2004

#315 - Facade (Guest starring Rickey Gervais)
After a plasma charge goes off, killing several people and destroying a whole building, the CIA takes the bomb-maker into custody. In order to learn how to dismantle a second charge, the agency must sconvince him he is actually in Russian and that they work for the Covenant. Only problem is, he only wants to deal with Sark.
Original US Airdate: 14th March, 2004

#316 - Taken
In order to gain access to the DSR facility, the Covenant take Dixon's kids hostage. The only way they will return them is if Dixon provides them with a Rambaldi artifact currently being studied by the agency. Dixon enlists Sydney's help, however when she finds the object she has her own questions as to why the Covenant want it.
Original US Airdate: 21st March, 2004

#317 - The Frame
Jack and Senator Reed open an investigation into the security breach of the Rotunda facility, leading Jack to conclude that Lauren is a mole. However, this forces Sark takes matters into his own hands and orchestrate a plan to take the heat off Lauren. Meanwhile, Syd and Vaughn face off against Kazari Bomani.
Original US Airdate: 28th March, 2004

#318 - Unveiled
A global cyber-attack is launched by The Covenant, invading hospitals and corrupting data in order to obtain information relating to 'The Passenger'. Meanwhile, Jack is placed in a difficult situation when he learns that Lauren is the mole he has been searching for. Will Vaughn accept the truth that his wife has betrayed him?
Original US Airdate: 11th April, 2004

#319 - The Hourglass (Guest starring David Carradine)
Vaughn struggles to maintain the illusion that he is happily married after learning Lauren's true loyalties. As Jack works on the leak, Vaughn and Sydney are sent on a mission to recover a monk of Rambaldi who has intel on the identity of 'The Passenger'. Meanwhile, Sloane's execution moves forward.
Original US Airdate: 18th April, 2004

#320 - Blood Ties (Guest starring Mia Maestro and Richard Roundtree)
Sydney and Jack are forced to work with Sloane in order to break a five-hundred year old Rambaldi code and track down Nadia Santos, Sloane's daughter and Sydney's half-sister. Meanwhile, after learning his father was a Rambaldi follower, Vaughn is captured by The Covenant and tortured by his wife for the location of The Passenger.
Original US Airdate: 25th April, 2004

#321 - Legacy (Guest starring Mia Maestro, Isabella Rossellini and Vivica Fox)
Katya Derevko assists Sydney and Jack in tracking down Sloane through his previous contact with Toni Cummings. Meanwhile, Lauren and Sark take matters into their own hands to uncover the secrets within The Passenger and Vaughn finally decides what he needs to do to stop them...he needs to kill Lauren.
Original US Airdate: 2nd May, 2004

#322 - Resurrection (Guest starring Mia Maestro and Isabella Rossellini)
The Rotunda is compromised as Lauren detonates a series of explosives throughout the facility on a raid to retrieve intel on the location of Rambaldi's Sphere of Life. In the chaos, Vaughn goes rogue to hunt down Lauren and Sydney is tipped off by an unexpected source revealing a secret she was never supposed to know existed.
Original US Airdate: 23rd May, 2004