Jeff Stone

Jeff Stone was a mineralogist who hailed from New Paris, Venus. The brother of Andy and Mary Stone, his life was forever altered by the Dalek invasion of his homeworld. He became one of the Skaran mutants' most noteworthy human opponents. During one particular assault, he was elected Earth's Chief of Defences, and successfully mobilised all the Earth's nations against a Dalek incursion which all other human leaders had deemed a lost cause.

Venusian life
Stone's involvement with the Daleks began when he was on holiday with his siblings in the Churchill Mountains. The Daleks attacked Venus and almost immediately captured him. (DAN: Invasion of the Daleks'')

Recognising that his skills as a mineralogist made him smarter than the average human slave, the Daleks forced him to work in a lab at a lead mine. Andy came to free him, but it was really Jeff's knowledge of the properties of lead azide which destroyed his local Dalek masters. The two then set out to find and free their sister. (DAN: Red for Danger)

Following a lead, they went to one of Venus' oil wells. The two devised a plan to disrupt the Daleks' authority over the well, now turned into a kind of concentration camp. Their plan succeeded, and they freed all the humans at the camp, but Mary had by this time been moved to Dalek headquarters at New Paris. (DAN: The Oil Well)

On the way to find her, Jeff noticed something odd about the height of the Winston Mountains. He supposed that the Daleks had built a new base atop one of the peaks. The Stone brothers then made contact with Vel Karneen, who was likely the first person in any sort of organised armed force that Jeff encountered. Using one of Karneen's copterjets, the Stones ascended the mountain peak and snuck into the Dalek base. Inside, they found their sister and a lot of enslsaved Venusians. Using only a metal button from his clothing, he fried the internal electrical system of the Dalek base. This freed all the Venusians, and forced the Dalek fleet to flee their new headquarters. Jeff was able to radio Karneen for help, though, which gave the humans the advantage. The Space Army fleet simply downed each Dalek ship as it emerged from the mountain hideaway. The entire Dalek fleet occupying Venus was destroyed. Thus, it could be fairly said that Jeff Stone freed his homeworld with a single button — and a little help from the Space Army. (DAN: The Secret of the Mountain)

found and freed their sister. Jeff later travelled to Skaro on a mission to gather information on the Daleks. On Pluto, he discovered a way to use the sun's rays to blind, then disarm, the Daleks. Later, he and his siblings discovered and defeated a Dalek plot to destroy Earth. (DAN: The Dalek Book)