 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. Meanwhile, Vaughn s obsession with tracking down Lauren is beginning to consume him. During a mission to Cuba to uncover more Rimbaldi findings, Sydney and Vaughn turn the tables on an old foe; the Taiwanese scientist and torturer "suit and glasses. Also, Katya expresses her attraction to Jack.