It can enable a CD player's laser to shoot a plane from the sky or slice a tank in half. A Jakarta faction has employed Cesar Martinez, an Argentine resident, to acquire it for them. Nadia knows him - she recalls stealing from a restaurant owner with him as her accomplice.

Nadia reports that Martinez is a freelancer, and he earned his reputation with the execution of former Argentine intelligence officer, Roberto Fox. Their mission is to outfox Martinez and obtain the Amplifying Glass at a party held in the Minsk's Institute of Science. As the team left the room, Nadia admits to Sydney that she knows Martinez.

A blonde Sydney arrives at an elegant party in the Institute of Science. She charms an architext, whose Blackberry holds the building's blue prints and project files. After scanning and decrypting his PDA with Marshall's help, Syd waits for Nadia, who has stolen a key from one of the scientists.

Later, Nadia spots Cesar Martinez. Nadia again flashes back to her teenage years. She's crying in the corner of a jail cell. Roberto Fox recruits her to work in espionage for the government. Nadia consults the headmistress of the orphanage, who encourages her to take the job. At the party, gunmen open fire as Martinez follows Sydney's path.

In the lab, Syd cracks the safe and retrieves the Amplifying Glass. When Martinez and his thugs enter, Syd surrenders the Glass. Martinez asks Sydney who she works for, Nadia arrives and says, "She works with me." He recognizes Nadia, and ties her and Syd up.

Back at APO, Sloane reprimands Nadia for not sharing her past regarding Martinez. Nadia insists she can get the Glass back from Martinez. She doesn't tell them that she actually worked with Martinez under Roberto's tutelage.

In Buenos Aires, Nadia sits at an outdoor restaurant while Sydney and Weiss observe from a van. Martinez arrives and although Nadia convinces him to sell the glass to her, he demands that she accompany him back to his office without -- tracking and backup. Nadia agrees despite Syd's reservations.

Martinez asks Nadia if she still thinks about Roberto Fox. Nadia recalls finding her dying partner, who says that Roberto Fox is a criminal who had them steal government intelligence. Nadia thought she'd been working for the Argentine government.

Martinez says he didn't kill Fox. It was Nadia who shot the traitor in the chest. When Nadia says she'd do it again, Martinez points a gun at her. She knocks it away and hits him. Nadia grabs the gun and points it at him. Sydney arrives with Weiss. Nadia tells them that the Amplifying Glass is in the safe and Weiss takes Martinez away. Sydney and Nadia embrace.

In Lisbon, Vaughn finds the address mentioned in his father's journal. The door opens to reveal Nadia's headmistress at the orphanage! She says the only time she met Vaughn's father was when he came to her, covered in blood with a baby in his arms - the baby was Nadia. Pressed for further details the headmistress says she heard his father mention one particular word during a phone conversation - "nightingale."