Marketing relied heavily on the public's nostalgia for the series, with products taking inspiration from all four films. Anticipation for the film was heightened by secrecy, which resulted in a legal dispute over an extra violating his and the arrest of another man for stealing a computer containing various documents related to the production. Indiana Jones and the Kingdom of the Crystal Skull was released worldwide on May 22, 2008, and was a financial success, grossing over $786 million worldwide, becoming the second highest grossing film of 2008. The film received mostly positive reviews from critics, but fan reaction was mixed.
Plot:
In 1957, Colonel-Doctor Irina Spalko and a convoy of agents posing as infiltrate a military base in the desert. They force to lead them to a crate in "", which holds the remains of an creature that in . Indiana attempts to escape but is foiled by his partner George 'Mac' McHale, who reveals that he is working with the Soviets. After a fight and an elaborate vehicle chase through the warehouse, Indiana escapes on a into the desert, where he stumbles upon a and survives a by hiding in a -lined refrigerator. While being debriefed, Indiana discovers he is under investigation because of Mac's Soviet ties. Indiana returns to Marshall College, where he is offered an indefinite leave of absence to avoid being fired because of the investigation. At a train station, Indiana is stopped by Mutt Williams and told that his old colleague, Harold Oxley, disappeared after discovering a near the in . Indiana and Mutt go to a local diner, where they discuss the legend of the skull and the mythical city of . Mutt passes Indiana a letter from Oxley, which contains a riddle written in an ancient Latin American language. Soviet agents approach them, and a chase commences on the college grounds. Indiana realizes that the Soviets were trailing Mutt to get him to decode Oxley's letter.
In , Indiana and Mutt discover that Oxley was locked in a church-operated until the Soviets kidnapped him. In Oxley's former cell, Indiana discovers clues to the grave of , a who went missing in the 1500s while seeking Akator. Indiana and Mutt follow the clues to Orellana's grave, where they find the crystal skull; Indiana reasons that it had been hidden there by Oxley. The Soviets capture Indiana and Mutt and take them to their camp in where they are holding Oxley, and Mutt's mother – who turns out to be Indiana's old love, . Indiana learns that the Soviets believe the skull is from an extraterrestrial life-form and holds great power; Oxley has suffered a due to over-exposure to the skull's powers. Spalko reveals the specimen stolen from Hangar 51 also has a crystal skull; Spalko believes that returning the skull to Akator will give the Soviets control of the skull's psychic power for use in warfare. As the four attempt to escape from the Soviets, Marion reveals that Mutt's real name is Henry Jones III and that he is Indiana's son. They finally escape in an , leading to a lengthy vehicle chase involving a sword fight between Mutt and Spalko, Mutt swinging on vines with monkeys, and a swarm of killer ants.
After surviving an attack by Ugha warriors defending the temple, Indiana, Mutt, Marion, Oxley, and Mac arrive at the Temple of Akator, a Mayan-style pyramid in the . Claiming that he is a working against the Soviets, Mac enters the temple with Indiana and the group, but he is actually leaving a trail of homing devices for Spalko to follow. The group enters the temple and Indiana uses the skull to open the door to a , where thirteen crystal skeletons, one missing a skull, are seated on thrones. After the Soviets arrive and again reveal Mac's complicity, Spalko places the skull onto a headless skeleton. It begins communicating to the group through Oxley using an ancient dialect. Indiana translates this to mean that the aliens want to reward them with a "big gift". Spalko approaches and demands to "know everything". The beings grant her request and begin to transfer their collective knowledge into her mind. As a portal to another dimension appears over the room, Oxley regains his sanity and explains that the aliens are interdimensional beings who taught the Ugha tribe their advanced technology, such as agriculture and irrigation. Indiana, Mutt, Marion, and Oxley escape from the temple, but Mac and the soldiers are sucked into the portal. The skeletons form into a single alien which continues to feed Spalko with knowledge; however, the collective knowledge of the thirteen beings is too much for Spalko. Her brain and body ignite and disintegrate – her scattered essence absorbed into the portal as well. The temple crumbles, and a rises from the debris and disappears as the floods the valley. After they return home, Indiana is reinstated and made an associate dean at Marshall College, and he and Marion are married.