|Series 06, Episode 03|
|Air Date||23 October 2007|
|Previous||"The Virus (Part 2)"|
Ros is abducted and tortured by Magritte, a French security officer, as part of a recruitment test for Yalta. Sholto, a Yalta representative, explains that the world-wide shadow organisation is named after the treaty that ended World War II and its aim is to stop the Americans from taking strategic actions that destabilise the world.
She is given evidence that Zaf is dead. Meanwhile, a cargo plane crashes near a US base. Ministry of Defense has established a cordon around the crash site, because the plane was carrying toxic chemicals, which later proves to be false. Adam and Malcolm infiltrate a UFO enthusiast group camped outside the base as a cover to break in. The two realise that the crash was caused by a prototype stealth plane "Aurora", which followed MI5 during their operation in Tehran, leading Adam to conclude the Americans are running "Copenhagen." Ros's anger at the Americans' latest actions in Tehran, Zaf's death, and now Aurora, leads her to cooperate with Yalta.