Legacy is the 21st episode of Season 3 of Alias, and the 65th episode overall. With the aid of Katya Derevko and CIA imprisoned security systems designer Toni Cummings, Sydney and Vaughn attempt to track down Sloane and Nadia. But Lauren and Sark are also in hot pursuit of them in order to uncover the secrets of Rambaldi. While Vaughn's obsession with tracking down Lauren is beginning to consume him, Sydney and Vaughn turn the tables on an old foe.