Alias - Season 4 - Eps 17: A Clean Conscience
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 he and Jack decide to tell their daughters the truth – Elena Derevko, the third and the most cruelest of the Derevko sisters, has been surveilling both Sydney and Nadia for a decade. Meanwhile, Jack's doctor advises him to tell Sydney about his illness.
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