Season 4

episodes

1. 1. Authorized Personnel Only (1) 2005-01-05 44 min 7.9 Sydney quits the CIA and joins a Black Ops unit called "Authorized Personnel Only" alongside Dixon, Jack, Vaughn and... Sloane. Meanwhile, the truth Sydney found out in Wittenberg endangers her relati...
2. 2. Authorized Personnel Only (2) 2005-01-05 44 min 7.8 Sydney unwillingly teams up with her father to hunt down a modern-day samurai. Meanwhile, Nadia doesn't want to go back to the spy business, but is forced to when Sydney's life is jeopardized. Sydney...
3. 3. The Awful Truth 2005-01-12 42 min 8.0 Sydney must seduce 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 argue about telling Nadia the truth about her...
4. 4. Ice 2005-01-19 41 min 7.9 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 Jack to find out the truth abo...
5. 5. Welcome to Liberty Village 2005-01-26 42 min 8.4 Sydney and Vaughn go undercover as a married couple so as to find a weapon that could bring back the Dark Ages. However, the neighborhood they've infiltrated is not as charming as it seems.
6. 6. Nocturne 2005-02-09 43 min 7.7 After being infected with a hallucinogen, Sydney starts to lose touch with reality. Vaughn and Jack must rush to find an antidote before Sydney puts her life - and others next to her - into danger.
7. 7. Détente 2005-02-16 41 min 7.5 While Sydney and Nadia argue about Nadia's acceptance of Sloane's fatherly concerns, Sloane worries about Nadia's well-being when she and Sydney go undercover as wealthy, irresponsible young heiresses...
8. 8. Echoes 2005-02-23 43 min 7.9 Sloane temporarily steps down as Director of his Task Force and gives Jack full authority over the next assignment, which involves Anna Espinosa, Sydney's old foe. However, Anna turns the tables on AP...
9. 9. A Man of His Word 2005-03-02 41 min 7.6 While Nadia is in a coma, Sark is taken into APO to help them infiltrate Cadmus Revolutionary Front and retrieve the bomb, but in return he demands to see Lauren's corpse and that Vaughn opens her cof...
10. 10. The Index 2005-03-09 43 min 8.1 Dixon enlists Sydney to help him prove that Sloane is double-crossing the CIA and using APO to steal the Blackwell Index, a master blackmail list, and to reconstruct the Alliance. Sydney makes her way...
11. 11. The Road Home 2005-03-16 42 min 7.5 Sydney must protect the life of a civilian, whom she unintentionally put in danger. Meanwhile, Jack plans a visit with an old friend, and Vaughn uncovers more disturbing secrets about his father.
12. 12. The Orphan 2005-03-23 44 min 7.4 Nadia puts her own life - as well Sydney's and Weiss's - in danger after failing to unveil her past through a dangerous criminal. Meanwhile, Vaughn finds a person who is somehow connected to his fathe...
13. 13. Tuesday 2005-03-30 44 min 8.1 When a mission goes wrong, Sydney's is placed in danger and Marshall is the only one who can save her. Meanwhile, Dixon is exposed to a deadly pathogen released inside APO.
14. 14. Nightingale 2005-04-06 43 min 7.9 Sydney and Vaughn risk their lives trying to find out the truth about Vaughn's father. Finally, we find out why Jack and Sloane seem to be conspiring together against Sydney and Vaughn.
15. 15. Pandora 2005-04-13 44 min 7.8 In an attempt to talk to Sydney, Katya Derevko deliberately poisons herself and is temporally taken out from her cell. Once Nadia tells her sister about this, Sydney visits her aunt to tell her to sta...
16. 16. Another Mister Sloane 2005-04-20 43 min 7.9 Sydney and Vaughn tell Jack about Sloane's alleged involvement in Vaughn's search for his father and Irina's contract on Sydney's life. After cornering Sloane, they both conclude that someone is frami...
17. 17. A Clean Conscience 2005-04-27 43 min 7.9 Nadia's former caretaker, Sophia, has been severely beaten. She contacts Nadia and asks to meet her. Sloane is told by Sophia that she was beaten up, because someone is trying to track Nadia down, so...
18. 18. Mirage 2005-05-04 43 min 7.9 Jack's illness has caused him to hallucinate about a cure. Sydney must recreate the time when Jack was working for the CIA and hid the only man who might be able to help him now. For this, Sydney must...
19. 19. In Dreams... 2005-05-11 44 min 7.6 The team captures the Sloane Imposter and questions him to find a rare Rambaldi orchid. The real Sloane must relive a painful memory in order to get the Imposter to reveal the orchid location.
20. 20. The Descent 2005-05-18 44 min 7.8 After a tactical group infiltrates the DSR and steals Rambaldi artifacts, CIA director Hayden Chase discovers that the alarms at the DSR were disabled from Nadia's computer, allowing the raid to happe...
21. 21. Search and Rescue 2005-05-18 44 min 7.9 Rambaldi's catastrophic endgame begins to fall into place as a giant version of the Circumference/Mueller device is found floating over city in Russia, driving the citizens made. After a wounded Dixon...
22. 22. Before the Flood 2005-05-25 44 min 8.1 Jack, Sydney, Irina, Vaughn and Nadia parachute into Sovogda. They're supposed to dismantle a giant red ball turning people into zombies. At APO, Marshall and Weiss use the Blackwell Index to blackmai...