Amelia Grover

 was the daughter of Marshal Grover, and the stepdaughter of Nancy Norton. She was in a car accident which killed her mother and made her lose one of her arms.

Professor Sternberg convinced her father to finance an expedition to the island of Salutua in 1934. Ostensibly, it was to explore the island and film a King Kong-like movie, with real giant animals instead of special effects. But Grover hoped the cause of the animal's growth could help restore Amelia's missing arm. When the ship was attacked by giant crabs, Nancy accidentally knocked Amelia overboard and she had to flee into the woods. After falling into a pit, she encountered a giant spider.

Because the Third Doctor created a time bridge to the island from UNIT in the future, several potential timelines were created. (PROSE: The Eye of the Giant)

Original timeline
The giant spider probably killed her. If it didn't, then she died with the expedition when the volcano on the island erupted after Brokk's ship crashed into it.

Alternate timeline 1
Mike Yates rescued her. When Nancy fused with Brokk's eyebrain, Amelia committed suicide to evade her control.

Alternate timeline 2
She did not take the last Semquess drug, and was killed along with everyone else on Earth by the Nancy-Brokk-ship hybrid.

Alternate timeline 3
She took the last Semquess drug and transformed into an angelic being. She stopped the Nancy-Brokk-ship hybrid and left Earth with it, hoping to eventually separate the composite creature.