About this episode
Two alien soldiers, locked in a bitter duel to the death, take their titanic struggle to the new world order of modern Earth. Motuth and Ossup use fanatical patriots on both sides of the shattered Iron Curtain, beginning a chain of events that might end in the extinction of the human race…unless the Doctor can stop them. The Doctor and his companions are lured into the crisis like chess pieces onto the game board by a mysterious being who reaches out to the intrepid Time Lord’s mind. But once the Doctor discovers the danger, he joins forces with his reluctant and mistrusting friends at UNIT. Together, they embark on an international search for the aliens. As they come closer to the truth, the Doctor and his companions experience horrors and personal demons that no one would dare anticipate. Friend is turned against friend, innocent lives subjected to cruel experimentation, and all the while, the threat of cosmic power left unchecked and out of control lurks in the shadows.