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Norna was a member of the human colony on Frontios. She was the daughter of Range.
She helped her father in his science-related workings. When the Fifth Doctor came to Frontios, Norna helped him aid the sick.
Norna told Tegan and Turlough that an acid jar could be used to power the phosphor lamps to be brighter. She bargained with Plantagenet to be allowed entrance to the research room on the colony ship. Once inside, she helped Tegan and Turlough sneak in. They levered an acid battery out of the ship and carried it back to the Doctor.
Norna and Turlough returned to the research room and explored the caverns beneath it. Norna was captured by Tractators, as was the Doctor. They were freed when Tegan threw a phosphor lamp among the Tractors and it exploded.
Turlough was sent into shock due to an ancestral memory of the Tractators and Norna was left to care for him. She returned to the surface and was captured by Cockerill and his fellow deserters, who left her bound and gagged. She freed herself from her bonds with a knife and told the deserters Plantagenet had not been killed. They followed her into the caverns to see for themselves.
After the Tractators were defeated, Norna and the other colonists bade farewell to the Doctor and his companions. The Doctor told them not to speak of his visit to the colony as it defied the Time Lord non-interference policy. (Frontios)