Hilda Winters was a member and leader of the Scientific Reform Society, a group secretly planning to take over Earth. Twenty years later, she made numerous attempts to destroy Sarah Jane Smith, and eventually, the city of London.
Ms. Winters was acting as the Director of the National Institute for Advanced Scientific Research, when she was asked by UNIT to give journalist Sarah Jane Smith a tour of their facilities, and to display their Experimental Prototype Robot K1. When Winters demonstrated its inability to kill by asking it to terminate Sarah's life, the robot became confused, claiming that such an order conflicted with its prime directive.
Within a few days it became clear that Winters was also the leader of the Scientific Reform Society, a group that felt the world should be forcibly ruled by the scientific elite. The group used the robot to obtain the nuclear missile codes of all nations in order to blackmail the United Nations with the threat of a nuclear holocaust.
Winters and the other Society members retreated to their nuclear bunker, with the Robot defending them. However, the Robot accidentally disintegrated its creator, sending it into a rampaging confusion. The Fourth Doctor shortly defeated the robot, got into the bunker with UNIT's help, and reprogrammed the Society's computers before any nuclear missiles could be launched. Winters and the Scientific Reform Society members were caught and arrested. (TV: Robot)
After serving fifteen years in prison for her crimes, Winters was determined to exact revenge on Sarah Jane by framing her for a terrorist attack on the London Underground and the murder of Claudia Coster, although she hired henchmen to carry out her work so that Sarah Jane wouldn't detect her presence. (AUDIO: Test of Nerve)
After this, Winters contracted Abbotly to disrupt a peace conference in Romania using a deadly new experimental sound technique. When Sarah Jane showed up to investigate the first death resulting there, Winters expanded the contract to include her. Again, Sarah Jane solved and foiled the plot, but Winter's role in the affair went undetected. (AUDIO: Ghost Town).
At this point Winters took the affronts personally, and vowed to see Sarah Jane dead by whatever means necessary. First she had some associates break into Sarah's house and steal the non-functional K9 Mark III, then worked to frame Sarah for the planned release of Brucella bacteria into the Indian water supply. During this time, Hilda and Sarah Jane encountered each other for the first time since 1974. Hilda's plan was once again foiled, but she escaped to continue her vendetta elsewhere. (AUDIO: Mirror, Signal, Manoeuvre)
Three years later, Sarah Jane received news that Hilda had died whilst under arrest, and felt a slight remorse for her, even though she considered Winters one of her greatest enemies. Sarah received a letter shortly afterward from Hilda, warning her about the Crimson Chapter of the Orbus Postramo, and that the Book of Tomorrows was opening. (AUDIO: Buried Secrets)
It was later revealed that Winters was a member of the Crimson Chapter, sent to test whether Sarah Jane was the herald described in the Book that would help bring about the prophesied End of Days. When Ms. Winters took the job a bit too personally, she proved herself a liability to the Chapter, and they had her killed for it. (AUDIO: Fatal Consequences)