After Indiana Jones left Marion Ravenwood a week before their wedding, she gave birth to a son who she named Henry Jones III. Marion went on to marry Colin Williams, who Mutt was led to believe was his biological father. Mutt also befriended Professor Harold Oxley, who became a surrogate father to him when Colin was killed during World War II.
Search for OxleyEdit
When Oxley went missing in Peru, Marion followed and ended up disappearing as well. She managed to get a letter to her son telling Mutt to find Jones. He caught up the archaeologist just as he was leaving on a train to New York City, having decided to leave the country for London.
After convincing Indiana to come along with him, they go to a diner, where Mutt delivers a letter sent by his mother, "Mary Williams". But then two KGB agents who were watching tried to capture the duo, only being stopped by Mutt starting a fight between the Greasers and Socialites. The archaeologist and his new sidekick get away on Mutt's motorcycle, and a chase through the Marshall College campus begins, ending when one of the two persuing Russian cars crashes into the statue memorial of Marcus Brody.
After Indiana and Mutt solve the riddles written in dead language from the letter, they go to the possible location of Oxley - Nazca, Peru. There, in an old spanish tomb, they found a Crystal Skull that Oxley had returned to where he had found it.On their way to the tomb Mutt gets stung by a huge scorpion and thinks that he is going to die but Indy tells him not to worry, the bigger the scorpion, the better. As they were leaving the tomb, a group of Russian agents captured them. The agents took them to their camp, where Mutt was reunited with Marion. Unfortunately, Oxley was also at the camp, and was insane from the Crystal's power.
Mutt later created a diversion for the group to escape, but they were recaptured. After this, his mother told him that Indiana was his real father. The group later made another escape attempt, during which Mutt fought Irina Spalko. After escaping the Russians, the group came to the temple where the Crystal Skull was supposed to be returned, where the Russians caught up with them again. When the Crystal Skull's power was activated, the group escaped again.
Mutt later attended his parents' wedding.