"Gruber's a good man, but he gets possessive about whatever he's assigned to protect."―Marcus Brody[src]
In 1931, there was a worldwide series of thefts of Wohat Statues from different museums. Gruber, hoping to capitalize on the crime spree without getting caught, plotted a copycat theft to have the Wohat crocodile stolen from his own museum. He hired two goons to steal the artifact at night, and during the heist, he encountered them in a standoff, reminding them to not hit him with the crocodile figure as they knocked him out and tied him up.
The next day, he met with Marcus Brody at Marshall College, who took him to Indiana Jones, whom Gruber had known by reputation as infamous. Jones immediately guessed that Gruber was there about the Wohat statue thefts, and related the history of Wohat, Ali Bey, and the Invincible Ruby. Gruber appeared uninterested in the ruby's mystical powers, claiming he was solely interested in recovering his lost crocodile statue, and left in a huff.
Gruber traveled to Barcelona, and broke into the Barcelona History Museum at night, where he met Dr. Jones again, who had arrived to investigate the theft of that museum's Wohat lion. The pair decided to team up to investigate the string of thefts, and were assaulted by a man in a fez and his henchmen. Gruber claimed that these were the same men who had stolen the crocodile in New York, before appealing to his new partner to rescue him. The man in the turban grabbed Gruber, who then tried to bargain with their leader. Not seeking a deal, the man in the fez and the third thief sealed Gruber into a mummy's sarcophagus.
Gruber eventually escaped and tracked Jones or the fez-wearing Ali Bey-Faisal to the ruins of Ali Bey's Palace in Kenya. After Jones had solved how to enter the palace using the five Wohat mammal statues, Bey-Faisal appeared and held him at gunpoint. Gruber then stepped out of the jungle and pistol-whipped Bey-Faisal, rescuing Jones, and requested to partner up again. After Jones knocked out one of Bey-Faisal's henchmen, the pair darted into the dark ruins. Overhearing that Bey-Faisal was not making progress in finding them, Gruber surmised that they had lost their pursuers, but Jones felt that that their safety was not assured in the place. The floor gave way beneath them, and Gruber and Jones tumbled into a lower burial chamber, where the two were knocked unconscious.
Recovering his senses, Gruber picked up his pistol and found Jones examining a box carved by Wohat. Pushing the lid off, the two discovered a large ruby, which Gruber surmised was Ali Bey's invincible ruby. When Jones suggested taking it to the university for testing, Gruber pulled his gun on his partner, revealing his treachery. Jones confronted him on the fact that he knew that Gruber had stolen the crocodile statue, and not René Belloq's men, because Belloq and Bey-Faisal were only interested in mammalian statues. Eventually, Gruber admitted to the theft and drew his gun to silence Jones. The trigger clicked on an empty chamber, as Jones had pilfered the bullets while Gruber was unconscious.
Gruber tried to seize the ruby, but Bey-Faisal, who had overheard their exchange, rushed into the chamber and grabbed Gruber's arm. Gruber punched Bey-Faisal over, then reached in and picked up the ruby. Claiming that the ruby was safe to hold, Gruber held it over his head. The ruby shot out intense red light, and a screaming Gruber was reduced to a smoking pile of ash. His vaporization started the collapse of the palace, leading to the death of Bey-Faisal and likely his henchmen.
"I read about it...read about the power that is within it...You want to keep me from it...but that will not happen! Even with all its power, the ruby is safe to the touch... see?"―Ballantine Gruber[src]