"Imagine my surprise when I eventually found him and discovered that he was a madman living in a cave. Hiding a secret that I could not leave unguarded."
About 1934, he traveled to Tibet to find out why his father had left their affluent life to live in a cave. He discovered that his father had gone truly insane, from trying to understand and protect the secret of the Tomb of the Gods. In mid 1935, Alex watched his father die from alcoholism and madness, and took up his father's mantle in ensuring that his father's piece of the key did not fall into the wrong hands. At some point during his time in Tibet, he became a Buddhist monk, though did not remain so for long. After his father's death, he lived in the cave, and studied the markings on the key, and the carvings his father left on the cave walls.
In the summer of 1936, suspecting that the Nazis had finally found the cave, he hid with his rifle outside his cave. When two Westerners entered the cave, he threw a bundle of dynamite inside. The cave was collapsed, but one survivor exited and surrendered to him. As he aimed to capture the man, a bullwhip came out of the smoke cloud and disarmed him. Now the prisoner of the two men, he affirmed that he was Beresford-Hope, but his captors, Marcus Brody and Indiana Jones realized that he was not Sir Francis, but his son. Realizing that they were not Nazis, he told them of his father's death, and his new role protecting the secret. The explosion had drawn the attention of a band of Tibetan bandit horsemen, who charged the three men, who fled from the cave site.
Beresford-Hope teamed up with Brody and Jones, and escaped with them on a plane, accidentally taking a Tibetan Bandit with them. After the bandit was forced off the plane, Beresford-Hope showed his new allies the piece of the key that his father had kept. He and Jones decided to travel by freighter toward Siberia to find out what the key opened, and prevent the Nazis from reaching it first. Unfortunately, Friedrich von Hassell and Janice Le Roi had slipped aboard the ship when it docked in Japan, and Beresford-Hope was taken prisoner to guide the Nazis, while Jones and Le Roi were abandoned in a sinking rowboat.
When von Hassell reached the inlet marked on the map, he set out across the icy Siberian countryside on dog-pulled sledges, keeping Beresford Hope as his captive and information source. When Jones, Brody and Le Roi caught up to them, Jones attempted to seize one of the sledges. With von Hassell distracted by Jones' actions, Beresford-Hope grabbed his captor. Jones called out to him, trying to get him to jump to Jones' sled. A lightning bolt hit the ice ahead of the racing sleds, opening a large crack in the ice, and all the sleds fell into the darkness.
Surviving the fall into the chasm, Beresford-Hope was recaptured by the Ahnenerbe men, and traveled down the icy passageway to the large underground cavern housing the giant Tomb of the Gods. He, along with a captive Brody, and von Hassell stared at the incredible sight. Von Hassell regained composure and ordered the two captives into the entryway of the mammoth structure. Upon viewing the star charts in the ceiling of the antechamber, Beresford-Hope commented that the Nazis had no way to reach the stars - a sentiment rejected by von Hassell, who remarked on Nazi progress in rocketry. Von Hassell drew his pistol on Beresford-Hope, ordering him to enter the tomb. Beresford-Hope related that his father, along with Marwell O'Brien and Henrik Mellberg, had previously found the tomb, in a party of fifteen men -- and only three returned alive - and lost their sanity. Threatened with death, Beresford-Hope bravely refused to help von Hassell, and kept his father's promise to protect the Tomb from those seeking its power. Realizing that the young man would not change his mind, von Hassell slid out the blade in his sleeve and cut Beresford-Hope down. From his hiding place, Indiana Jones watched Alex Beresford-Hopes's death, and eventually avenged him by killing von Hassell and destroying the Tomb of the Gods, preventing others from finding its secrets.
Beresford-Hope's body was lost when the Tomb collapsed.
"Knowledge for its own wonder is something close to heaven, I think. Knowledge for the pursuit of power and glory, however? That is the road to hell. So you and your Führer can bugger off. I'm not doing it."
―Alex Beresford-Hope, final words[src]