Alias - Season 4 - Eps 22: Before the Flood
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 blackmail the Russian minister into giving them the access codes to a Russian satellite, they discover that Elena is uplinking the satellite. A CIA agent, Brodien reminds them that the Rambaldi device is broadcasting a subaudible frequency that physiologically alters people who drink it and it is irreversible. Elena learns of the APO team's arrival.
About Alias

Title: Alias
First Air Date: 2001-09-30
Last Air Date: 2006-05-22
Status: Ended
Rating: 6.736/10 (from 645 votes)
Language: EN
Seasons: 6
Total Episodes: 105
Network: ABC
Genres: Action & Adventure, Drama
Production Companies: Bad Robot, Touchstone Television
Synopsis
Sydney Bristow, an agent who has been tricked to believe she is working for the U.S. government, is actually working for a criminal organization named the Alliance of Twelve. Upon learning this, Sydney becomes a double agent for the real CIA.
Cast

Jennifer Garner
Sydney Bristow

Michael Vartan
Michael Vaughn

Victor Garber
Jack Bristow

Ron Rifkin
Arvin Sloane

Carl Lumbly
Marcus Dixon

Kevin Weisman
Marshall Flinkman

Rachel Nichols
Rachel Gibson

Amy Acker
Kelly Peyton