“Authorized Personnel Only”

Alias season 4, episode 1
Original air date: January 05, 2005

Sydney gets called up in front of the CIA brass for a botched operation in Singapore, during which she endangered an undercover informant's life. She gets fired by the tough new Director, but it turns out that she's really just being brought underground to a black ops outfit known as APO — Authorized Personnel Only — to which Vaughn, Jack and Dixon have already been recruited.

They're all stunned, however, to learn that the new head of APO is none other than Sloane. Sydney confronts the Director about trusting Sloane, but she informs Sydney that what they're trying to create is another SD-6, although operatin for the U.S. government instead of against it. So, who better than Sloane, with his contacts and expertise in such operations, to run it?

Their first mission is to obtain an unstable isotope from a Russian scientist who is selling it to a buyer known as "Mr. Vadik." Vaughn stands in for the scientist to meet the buyer, while Sydney keeps the actual scientist busy in his cabin and steals the isotope. Unfortunately, the buyer's agent, a modern samurai named Tamuzaki, figures out that Vaughn's not the scientist, and he and Sydney have to fight their way off the train.

They do, but Sydney has to track Nadia down in Argentina to get information about Vadik, because one of her Argentinian colleagues was undercover in Vadik's organization and was killed. Nadia does not yet know what Sydney does — that Jack killed Irina. Regardless, Sydney can't persuade her to return to the CIA with her. Nadia says she's out of the game for good.

To get Tamuzaki's attention, Sydney steals a samurai sword from a museum in London. To accomplish this, APO brings Marshall on board to run their tech ops as always. Tamuzaki agrees to meet to buy the sword, but he ambushes Sydney in an underground parking lot. He tortures her with a water treatment that forces water at high pressure through a mask, not allowing her to breathe. He assumes that she's there because she knows his secret — that Irina had put a contract on Sydney's life. Sydney's not aware of this, but she kills Tamuzaki after he tells her this. Nadia, meanwhile, has obtained some intel: Tamuzaki is Vadik, just under a pseudonym.

Sydney now understands why Jack killed Irina, but she knows that Nadia will not understand. She and Nadia visit their mother's grave together, and Nadia vows to hunt down the man that killed Irina and make him pay.