Jack takes action to abort Syd's continued work with Irina, who holds the key to cracking Sark's plans for a Russian satellite armed with heavy-duty abilities. Meanwhile, Will comes face-to-face with Vaughn, who needs him to revisit his ordeal in Taipei; and Sloane gets the creepy suspicion that his late wife may not be so late, after all. Barnett: Patricia Wettig. Kendall: Terry O'Quinn. Jack: Victor Garber.