Production code
October 21 2001
Written by
Alex Kurtzman
Story by
Teleplay by
Directed by
Mike Saloman

Parity is the third episode of Season 1 of Alias. Sydney's life is in mortal danger as she is sent to Madrid to retrieve a 500-year-old sketch that contains a set of numbers and meets up with her deadly nemesis, K-Directorate agent, Anna Espinosa. Meanwhile, Will delves deeper into the cause of Danny's death and discovers a very strange anomaly.

Plot Overview[]

Sydney is holding the nuclear weapon's plutonium core in her hand, when Hassan catches her -- and puts a gun to her head. Using the core as a distraction, she knocks Hassan out, and dodges soldiers' bullets as she escapes.

Upon return, Sloane sends Sydney and Dixon to Madrid to steal a lockbox, containing a sketch with what appear to be digital code only drawn in the late 15th century by a seer named Milo Rambaldi. There are two sketches, containing the entire code, only when seen together and SD-6 needs the second one. However, a rival Russian agency is also after the sketch, and Sydney discovers that she is up against her deadly K-Directorate rival, Anna Espinosa, whom we identify now by the eye tattoo on her hand.

In secret, Sydney meets Vaughn along the Santa Monica pier, and tells him about the sketch but Vaughn also informs her that he's been taken off of her case, and a senior officer assigned in his place.

In Madrid, Sydney visits a show at the Auto Museo owned by Eduardo Benegas, where the box is hidden, while Dixon monitors outside in a van. She discovers that Anna is also there and one step ahead – she has the lockbox. But only after an intense fight, Sydney takes possession of the box.

Back home, Will is still curious about Danny's murder. But after requesting surveillance footage from traffic cameras around Danny's former apartment on the night of the murder, he discovers that all of these cameras went out within a mile of the apartment on precisely that night.

Later, he and Sydney get a little drunk after an evening out, and later at her apartment, a playful moment turns into a kiss and a moment of shocking discomfort for them both.

Meanwhile, Francie leaks that she and boyfriend Charlie haven't been intimate in a while and that she is worried. Sydney suggests it's because he's been busy until Francie discovers that he had no law review the previous night. When Charlie assures Francie that he is not having an affair, she is satisfied, until later discovering a matchbook with a woman's name and phone number.

Back at SD-6, Marshall cannot open the lockbox, and if he forces it open, a concealed piece of technology inside will destroy the sketch. Knowing that Anna has the key to the lockbox, Sloane arranges with K-Directorate for Sydney to meet Anna in Berlin, open the box and view the sketch together. Sloane knows that K-Directorate doesn't know that there are two sketches that make the entire code.

Sydney meets with special agent Seth Lambert, a senior CIA agent who has been assigned as Vaughn's replacement, to go over her Berlin assignment. But Sydney takes an intense dislike to him, and orders him to get Vaughn back on case or no results!

Arriving in Berlin, Sydney is wearing a CIA wire, and is relieved to hear Vaughn's voice in her earpiece - he's back. Both SD-6 and K-Directorate have positioned snipers on the bleachers of a stadium, in case either side attempts a double-cross. Sydney meets with Anna and exchanges words an intense psychological game is always at play. But when Anna opens the lockbox, both agents are horrified, as a sizzling sound emits from inside.



Guest Starring[]





  • The episode's title, "Parity", is a computer reference. A parity bit is an bit at the end of a byte used for error detection. It's association to this episode seems to be the relationship between Sydney and Lambert, and his supervising of her progress.
  • This is the first episode to reference Milo Rambaldi.
  • This is the first episode to reference Anna Espinosa.
  • In this episode Marshall states that "the concept of zero has been around well, it precedes Christ. The numeral one has been around even longer than that. Actually, Ptolemy used zeroes and punctuation. In Indian text, zero is more of a spiritual concept than a number."
  • Goof: When Sydney is chasing Anna through the basement after Anna stole the briefcase from the vault, Sydney removes her high heels on a stairway, to run faster. A couple of edits later, we see Sydney round a corner, briefly we can see her wearing RUNNING shoes a moment later we see her barefoot again. And she is clearly barefoot again when she begins her little brawl with Anna!
  • Number 47: The model of the car is Quantum 6 27 -110. The "Remote Modem" has a number on it. The number is [[1]]. When added up, they come to 47. The lock descrambler freezes at 6 7 8 3 0 0 5 2 9 9, once again added up it comes to 47.
  • The set in which the car is displayed in Madrid is the same set that was used in the episode That Old Black Magic of Charmed as a museum.
  • First kiss for Sydney and Will.

Aliases Used[]



Marshall's necklace


  • Necklace: The necklace had fibreglass pearls that were better for transmitting vibrations from one's larynx to the microphone in the pendant.
  • Spanish peseta: The currency of Spain before the introduction of the Euro, Marshall used the coin as a Sonic wave emitter. He also gave Sydney a pen which had a button that activated the coin, causing an explosion that shattered any glass within a nearby distance.
  • Remote modem: After wiring the device into the central junction box, the video signals in the building could be looped so Sydney could not be tracked via CCTV.


  • "The Beginner" by Miranda Lee Richards
  • "La Cienega Just Smiled" by Ryan Adams
  • "Rings A Bell" by Bill Bonk
  • "Go Get It" by Spookie Daly Pride

Allusions and References[]

  • Marshall: ... you'll probably want to dress nice, you know, dress to thrill.
A play on Dressed to Kill, the title of four movies, one of which is an adaptation of a Arthur Conan Doyle's story and the more recent one was directed by Brian De Palma in 1980.


  • Sydney: (to Lambert) Are you insane? Calling me in here for a social event? SD-6 has a division whose sole responsibility it is to track their agents and report back suspect activity. "Your girl" is risking her life, and you yours, every time we lay eyes on each other. So, do me a favor. Don't be so friendly.