Alias - Season 4 Episode 8
Echoes

Sloane temporarily steps down as Director of his Task Force and gives Jack full authority over the next assignment, which involves Anna Espinosa, Sydneys old foe. However, Anna turns the tables on APO when she captures Nadia and forces Sydney to do her biddings. Sydney tells Nadia about the Rambaldis prophecy which dictates that two sisters will fight and only one will survive. Meanwhile, Vaughn visits Sark and tries to trick him into helping them to catch Anna. In the end, one of the sisters is mortally wounded by Anna.