The Dalek Leader was the commander of a Dalek advance invasion party which landed in Kent. Their arrival was noticed by a young mole who popped out of his hole for a look around. The Daleks, unaware of the presence of the mole, discussed their strategy. They plotted to quickly assemble a metal landing pad, so the rest of their party could have a place to land. The Dalek Leader planned to put down quick-setting liquid metal.
As the Daleks began to dump the liquid metal onto their landing site, the mole became intrigued by the new material. He soon learned that it would stick to him, so he popped away from it and back into the ground. He created a number of burrow holes underneath the newly-lain liquid metal. This made the surface unstable, which tilted the liquid metal sprayer out of alignment. Within seconds, all but two of the Daleks were been frozen in place by the off-kilter sprayer.