Alias: Double Agent

CIA agent Jim Lennox appears to be a double agent as, under orders from Sloane, he kills Wallace, his partner and fiancee, before she can expose him. The CIA is unaware of Lennox's status and Sydney and Vaughn are sent to retrieve him from the laboratory of Dr. Enzo Markovic, who was developing a weapon called Helix that Lennox and Wallace were after. Syd finds Wallace being tortured while Vaughn retrieves the Helix device. Under further analysis, the CIA scientists find that Helix is a device to reshape a persons genetic makeup to exactly resemble another, differentiated only by retinal scan. Lennox was doubled and they are unsure if they have the real one or Enzo in disguise. He does check out and he and Syd are sent to Poland to destroy another Helix device. Upon arrival, they discover the device was used on someone else. Also, Vaughn gets a message from someone claiming to be the real Lennox and that the retinal scan was faked. The real Lennox arrives in time to kill the doppleganger and save Syd. Later, Sydney and Vaughn go to bed under surveillance from the second Helix subject, the Francine lookalike.