- "I, um, also thought maybe I could come to your tent later? To discuss a little ... extra credit?"
- ―Lucy Giles[src]
Lucy Giles was a student at Vassar College, and the daughter of criminal mastermind Busby Giles. In 1936, she took transferred to Marshall College and took Archaeology 223, under Professor Indiana Jones, and two weeks later, accompanied the class on a field trip to a Hopi cave in Arizona, where she hoped to win the affection of her handsome professor.
However, she also had a secret agenda - her father was converting one of the Hopi caves into an underground criminal base, and after he had heard about Jones' proposed expedition, he had Lucy transferred to Marshall College to monitor Jones and act as a backup plan to keep Jones from reporting the operation.
One afternoon, while in the mountains outside the caves, Giles wandered away from the group and discovered an arrowhead. While reaching for it, she was ambushed by a small scorpion. Screaming for help, Giles summoned Jones and the class. With a carefully aimed flick of his bullwhip, Jones dispatched the creature and Giles embraced her professor in gratitude. As she was being escorted by Jones back to the car to return to camp, another student warned the professor that Warren was scaling up to the caves. When a rock slide started, Jones went to rescue Warren, and left Lucy under Joel's supervision to return to camp. After Jones and Warren emerged from underneath an overturned truck, Giles tried to check on the professor, but was interrupted by two armed men claiming to be from the Bureau of Indian Affairs, who scared the college team off of the premises.
Back in town, at the ice cream parlor, Giles tried to get close to Jones after he got off the phone with Marcus Brody, buying him a large sundae, and offering to visit him in private. Jones, on a mission to investigate the suspicious activity at the cave, declined, and headed out. Giles slipped out and joined up with her father at the underground construction site, and when Jones fought his way into the complex, she appeared, pretending to be a captive, which distracted Jones enough so that he was knocked out. When he awoke, Giles claimed that she had followed him from his tent, thinking that he was going to meet up with other female students, like Eva or Clair. Giles pretended to be a hostage in her father's scheme to force Jones to take his expedition home and never talk about the criminal plot.
After the college team packed up and left, Jones returned, and infiltrated the criminal hideout. Sneaking through the passages, he discovered Giles reading a magazine. Assuming that she was still a prisoner, he tried to rescue her, but she cried out for help, and Jones was quickly apprehended. Busby revealed that Lucy was his daughter, and after her education was complete, she would be joining the family business. After revealing that his plot and his way to dispose of Jones, Jones revealed that he had radioed the state police. As sirens approached, Lucy and Busby ran for the hangar, leaving Jones to fight off the construction thugs. Slower than her father, Lucy was grabbed by Jones, but took a couple swings at her former professor before falling into a pile of rope. After the state troopers arrived, she was arrested, but made one final pass at her cute professor, who declined, claiming to stick to tarantulas.