Indiana Jones and the Last Crusade (1989) begins with a flashback: the year is 1912, and a young Indiana Jones is on a horseback riding trip with his Boy Scout Troop in Utah. As part of their trip, the troop begins to scour caves, when they suddenly discover a man and his gang trying to steal a golden crucifix that belonged to a conquistador called Coronado. The troop takes the crucifix before the man is able to, but the man starts to chase them. The chase finally leads to a train, which is where Indy gets scarred from a bullwhip and where he develops his phobia of snakes. Not only that, the man (who is later called "Panama Hat"), eventually gets the crucifix back, but not without inspiring Indy to start a career as an adventurer/archeologist.
The film jumps forward to 1938 as Indy is once again battling "Panama Hat" for the crucifix. He takes the crucifix back and takes it to a museum, which is when he learns that his father has disappeared when looking for the Holy Grail. At first, Indy reluctantly agrees to begin searching for his father, but after meeting a beautiful woman called Elsa, he begins his search for his father and the Grail in earnest.
Eventually, Indy finds his father in a Nazi-controlled castle. It's there that he also learns that Elsa is a double-agent for the Nazis who was hoping get information to find the Grail before the Jones' were able to. After the two escape the Castle, they must undergo a number of trials before they are able to find the Grail.
Nevertheless, they eventually find the Grail in a temple. It is guarded by a 700 year-old Knight, who warns Indy, his father, and the Nazis who have accompanied him that those who wish to harness the power of the Grail must stay in the Temple - they (and the Grail itself) cannot leave. Elsa nonetheless tries to take the Grail outside of the Temple, which causes her to die and the Temple to collapse around them. The group escapes, and the film quite fittingly ends with a shot of Indy and his father riding off into the sunset, signaling the end of the trilogy.
