Alias (2001)

S4E20 The Descent

When a specialized team breaks into the DSR and makes off with Rambaldi artifacts, CIA director Hayden Chase realizes that the security alarms were disabled using Nadia's computer, prompting him to confront her at home. Shortly after, Sloane and Jack arrive, suspecting that Sophia, who had access to the computer during her time with Syd and Nadia, could be Elena Derevko. Their investigation leads them to a deceased Rambaldi acolyte, revealing a shocking betrayal and the possible return of a family member thought to be dead.