Captain Mike Yates and Sergeant Benton arrive at the village the following morning, but the Brigadier, arriving later, finds himself unable to enter the village, as there is an invisible dome-shaped barrier, 10 miles in diameter and one mile high, surrounding it that causes anything trying to enter to heat up and burst into flame. He contacts Yates and is briefed on the situation while the Doctor and Jo return to the dig where they find a small spaceship in the mound, which has been condensed. From this, the Doctor realises that the Master is trying to conjure up an ancient and all-powerful demon, who is seen on Earth to be the Devil but is actually an alien. The Doctor explains that the Dæmons have used Earth as a giant experiment throughout its history, becoming part of human myth. The Master has called the Dæmon up once, and right now, it is so small as to be invisible. The third summoning, however, could signal the end of the experiment, and the world.