Climbing over styrofoam boulders and pushing their way through plastic leaves and branches, Ian, Barbara and the small group of Thals continue their search for a secret way into the Dalek City via the mountains.
The viewer is treated to several ‘swaps’ between the journey of this small group and the one comprising of the Doctor and Susan.
The Doctor finds the Daleks audio/ visual transmitter and manages to mask their passing with a flashing light. While the Daleks are confused as the intermittent images they are receiving, they are informed by their scientists that they have the capacity to build a bomb which will emit a powerful enough burst of radiation which will kill all living creatures within the planet bar themselves. With the time frame of less than a earthly month, the set about to ensure the destruction of their enemies.
Meanwhile, the Doctor continues his streak of sabotage as he fiddles and blows up a control box to the computer terminals.(Remember that computers, even in the 25th century were housed in large rooms full of blinking buttons and spinning tapes)
Sadly for the Doctors group, they are quickly found and taken to the control centre where, as all evil characters are wont to do, tell them of their plans to take over the universe and destroy all enemies etc etc.
Flashing suddenly back to the other group, viewers are rewarded with a scene of the discover of a tunnel conveniently punched through the mountain to the city. The group begin ot argue on the ethics of killing and disturbing the peace they have had when huge styrofoam rocks tumble down the mountain, blocking the tribes chance to back out. Pressing on, they find other tunnels; however the landslide has caused huge crevices and a gaping abyss they must cross. Carefully, the tribe use a rope tied to Ian to cross. As the last member climbs over, he stumbles and falls into the abyss, dragging Ian with him….