In 1912, Boy Scout Indiana Jones lives with his father Henry Jones Sr. in Moab, Utah. One day, while undergoing a cave exploration, Indiana takes a crucifix owned by Coronado from a group of graverobbers led by a man named Garth, and after a brief horse chase, flees to his home. Garth, however, has the robbers retrieve the crucifix and gives him his fedora before leaving.
Twenty-six years later, Indiana successfully takes back the crucifix from the graverobbers' employer off the Portuguese coast. After returning to the United States, Indiana learns Henry has disappeared while searching for the Holy Grail. Walter Donovan, his father's financial backer, tasks Indiana with finding both Henry and the Grail. Indiana receives a package containing Henry's diary, which includes his research on the Grail, and travels to Venice alongside Marcus Brody to meet Henry's associate Elsa Schneider. Beneath the library where Henry was last seen, Indiana and Elsa discover a catacomb containing an inscribed shield which reveals that the path to the Grail begins in Alexandretta. The two are subsequently attacked by a mysterious group who reveal themselves to be the secret Order of the Cruciform Sword, dedicated to protecting the Grail. After saving the group's leader, he informs Indiana that Henry is being held at a castle in Austria. Indiana entrusts Marcus with a map from the diary detailing a route to the Grail and sends him to Alexandretta to rendezvous with their old friend Sallah. Discovering their rooms have been ransacked, Indiana reveals the diary's existence to Elsa before they sleep together.
In Austria, Indiana and Elsa infiltrate the castle, discovering it to be under Nazi control. Indiana finds Henry and tries to escape, but surrenders after Elsa is held captive by the Nazis. She reveals herself to be a Nazi collaborator, and Indiana and Henry are tied up and learn that Donovan is also working with the Nazis. After arriving in Alexandretta, Marcus is captured by the Nazis as well. Elsa returns to Germany, while Indiana and Henry escape the castle before travelling to Berlin to retrieve the diary. After recovering it from Elsa, Indiana and Henry flee on a zeppelin before evading two Luftwaffe planes pursuing them.
Arriving in Hatay, Sallah reveals to Indiana and Henry that the Nazis have also traveled there using the map. While they are following the trail, the Nazis are attacked by the Order but defeat them. Henry takes advantage of the distraction to try and rescue Marcus but is captured; Indiana attacks the Nazi convoy in response and is eventually able to destroy it with help from Henry and Marcus. Indiana, Henry, Marcus and Sallah proceed to a temple containing the Grail, where they observe the Nazis attempting to overcome the temple's traps before being captured. Donovan forces Indiana to find a way for them by mortally wounding Henry. With the help of the diary, Indiana overcomes the traps and finds a room with hundreds of cups and an ancient knight, who explains that only one cup is the true Grail. Donovan enters the room, dying by drinking from the wrong cup, before Indiana identifies the true Grail and rescues Henry. Elsa falls to her death when her attempt to leave with the Grail causes the temple's collapse. Indiana and his companions escape and ride off into the sunset.[3]
