The Secret of the Mountain was a pivotal prose tale in The Dalek Book. It closed the story arc of the Stone brothers' search for their sister, and it depicted humanity's first major victory over the Daleks since the invasion of the Solar System.
Jeff and Andy Stone are still looking for their sister Mary Stone when all the Daleks on Venus vanish. They're high atop Winston Dam with the newly-appointed commander of the Space Army, Vel Karneen, when something odd strikes them about the Churchill Mountains. The middle of its three peaks is distinctly taller than the two outer ones. The brothers immediately assume that the Daleks must have added to the mountain. Surmising that Mary is probably inside this new Dalek base, they ask Karneen for the use of a copterjet and set off to investigate the mysterious addition to the mountain.
Not wanting to trip any proximity alarms, they land far short of the peak and set about the arduous task of climbing the rest of the way. After some climbing they find a secret entrance behind a boulder. Inside is vast complex. Many of their fellow Venusians are there, being worked to exhaustion by the Daleks. In the crowd, they spot Mary. The brothers hatch a plan to free their sister and the rest of the Daleks' slaves. They try to control their excitement as they make their first contact with Mary for months.
Jeff sets about putting his plan into action. He jams one of his metal buttons into a light bulb socket, which fries the entire circuit. The cave goes dark. All the Venusians rush out of the cave. The brothers lead the people down the mountain, Jeff making a mad dash to the copterjet so he can radio Val for backup.
As the humans continue their descent, they notice the top of the mountain suddenly open up. Out streams the entire Dalek fleet. Just then, the Space Army fleet arrived. The two groups battle each other mightily, but the Space Army has the upper hand. Only one of the human vessels is downed, while the Dalek fleet is completely obliterated.
The Stone family consider what has just happened: they are reunited at last and the Daleks no longer occupy their world.
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- Why exactly the Daleks removed themselves to a secret lair in the Churchill Mountains is never revealed.
- It's also not explained why turning out the lights in the Dalek base would make the Daleks attempt to leave Venus altogether. However, the Stone brothers discuss the effect of their plan and confirm that it would be enough to drive their Dalek oppressors away.
- The idea of there being a space army linking together the worlds of the Solar System is something Terry Nation would use repeatedly. In The Daleks' Master Plan, Nation introduces the Space Security Service, and in the 1970s Dalek annuals, he comes up with the Anti-Dalek Force. There's no indication of an actual narrative connection between these three forces, but they fulfil the same narrative function.
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