In 1939, her mission was to collect the Staff of Kings, or at least prevent it from falling under Nazi control. She traveled to Panama, where she had the cover of being a photojournalist and hired the Boat Captain to take her upriver, where she planned to seek out the trail of Charles Kingston. At the boat dock, she met Indiana Jones, also seeking to go upriver, and she insisted that the boat was already hers, but the boat captain agreed to take them both. Reaching their destination, the two separated, though O'Malley helped Jones escape from some pillagers by pushing some boulders on them. Later she caught up with Jones after he found Kingston's Journal
The two went to Istanbul, Turkey where she said (covering up her true reasons) that she was there to cover the social event at the new museum. It was there that she ran into Magnus Völler, who revealed to her that he knew that she was a spy. She escaped from him and escaped with Jones on an elephant. From Istanbul, she and Jones went to Nepal where they set up camp in a cave. While Jones slept, she ran off in the cold to the local village and tried to enter the staff temple but was stopped by the Nepalese guards.
After Jones found his way into the temple and recovered the staff, she appeared and claimed the staff for her own. Believing her to be a Nazi, Jones confronted her, and she revealed that she was not a Nazi agent, but rather working for British intelligence. Magnus Völler and his gunmen appeared and kidnapped O'Malley and took the staff, trapping Jones in the temple. She was taken aboard the Odin where she was kept prisoner in a cell in the mess hall. Jones sneaked aboard and freed her. The two reached Völler and Kingston. As Völler attempted to shoot Jones, Kingston jumped into the way and was shot. While Jones tended to his dying mentor, Völler escaped, and O'Malley and Jones went after him.
Arriving on the sea floor with the waters parted by Völler and the Staff of Kings, O'Malley helped Jones race in a motorcycle with a sidecar after the Nazi archaeologist. Eventually, they caught up to Völler and reclaimed the staff and drove to the shore. After the staff restored the sea, O'Malley asserted her claim to the staff, though Jones put himself romantically in the way. The staff transformed into a serpent and slithered away, leaving O'Malley in Jones' embrace.