After dinner, Luke discovers that R2-D2 has escaped to find Obi-Wan Kenobi. Luke tells 3PO that it's too late to look for R2 because of the dangerous Sand People (also called Tusken Raiders) in the area, and that they will set out first thing in the morning to go look for him (hopefully before Owen discovers that due to Luke's negligence, his newest investment has disappeared).

During dinner, Luke tells his aunt and uncle that the droids may belong to someone called Obi-Wan Kenobi. This news greatly disturbs Uncle Owen, but he won't say why. Luke asks if Obi-Wan is possibly related to a hermit named Ben Kenobi who lives several miles away in the Dune Sea area, a vast terrain of sand and rocky canyons. Owen claims that Ben is "just a crazy old man," and that Obi-Wan is dead; Owen makes a comment which seems to indicate that Obi-Wan Kenobi knew Luke's long-deceased father, Anakin, but when Luke presses Owen for details, his uncle quickly changes the subject and instructs Luke to erase the droids' memories the next morning. Luke — who hopes to leave home for training at a nearby Imperial Military Academy to become a space pilot — leaves the room angrily to return to cleaning the droids. Luke's Aunt Beru (Shelagh Fraser) tells Owen that Luke is too much like his father to remain with them, but Owen holds out hope that Luke's desire for adventure will subside — and expresses a fear that Luke is too much like his father... suggesting that Owen may know something of Anakin's terrible pas

The Jawas travel to the Great Chott Salt Flat settlement to sell droids and equipment to local homesteaders, eventually arriving at the homestead of Owen Lars (Phil Brown), a moisture farmer. The farmer purchases C-3PO for his translation skills, as he is fluent in six million forms of communication, but initially decides to buy a cheaper utility droid, R5-D4, which breaks down almost immediately after purchase. Eager to deflect accusations of selling shoddy merchandise, the Jawas offer R2 as a replacement. Owen accepts and tells his young nephew, Luke Skywalker (Mark Hamill), to clean them up and put them to work. Luke had plans to meet some friends in the nearby town of Anchorhead, but his plans are put aside for work. During the cleanup, Luke stumbles across a short clip of the message stored in R2 by Princess Leia. The message is for someone named 'Obi-Wan Kenobi', and is a desperate plea for help. R2 insists that the message is simply a malfunction ("old data"), but Luke insists on hearing the complete message, intrigued by Leia's beauty. R2 then states that if Luke removes his restraining bolt, he might be able to play the rest of the message. Luke removes the bolt, but R2 doesn't play the message and claims not to know what Luke is talking about. Luke is called away for dinner (forgetting to replace the bolt, which will keep R2 within the boundaries of the moisture farm) and asks C-3PO to finish cleaning R2

However, Luke is too late. The Imperials have apparently come and gone, burned the homestead, and killed his aunt and uncle. Luke returns to Obi-Wan (who has used the opportunity afforded by Luke's trip to accord the massacred Jawas some measure of dignity), saying that with no reason to remain, he wants to go with him to Alderaan. More importantly, he declares his wish to learn the ways of the Force and become a Jedi like his father once was

A huge firefight ensues in the corridors of the Rebel ship, with many Rebel soldiers being lost in the battle. When the smoke clears, Darth Vader (David Prowse; voice: James Earl Jones), a man dressed in a black cape, black armor, and a black helmet that obscures all his features, briefly surveys the damage before interrogating the ship's captain, who claims that the ship is on a diplomatic mission to the planet Alderaan. Vader perceives that he is lying, noting that a consular ship would have an ambassador on board. (In actuality there is a diplomat aboard — Princess Leia Organa — but she is hiding from Vader, the second-ranking man in the Empire, which tends to support Vader's thesis that somebody on this ship is up to something.) Upon learning that "the plans" were not downloaded into the ship's computer, Vader strangles the captain. He then tells the troops to search the entire ship and to bring all the passengers to him — alive

Following the opening crawl, the frame moves down in the star field and we see a pitched battle between two starships in orbit around the desert planet of Tatooine. A small Rebel blockade runner, the Tantive IV, is being pursued by a mammoth Imperial star destroyer, the Devastator. Inside, protocol droid C-3PO (Anthony Daniels) and utility droid R2-D2 (Kenny Baker) are tossed about as their ship endures a barrage of laser bolts, and "3PO" concludes that escaping capture will be impossible. The Rebel ship is so heavily damaged that its main power reactor must be shut down. It is caught in the Imperial destroyer's tractor beam, pulled into the hold of the larger ship, and boarded by stormtroopers from the Empire's 501st Legion

C-3PO and R2-D2 manage to escape damage from the firefight. R2-D2 meets up with Princess Leia, who loads him with the stolen plans and records a holographic message for the small droid to take to the planet's surface. R2-D2 and C-3PO get away from the ship aboard an escape pod and go to the planet below; Imperial troops choose not to destroy the pod, as their scans detect no living organism on board, and presume it ejected due to a malfunction. Moments later the princess is stunned by Imperial troops and taken to Vader. He tells her that the Rebels have stolen some secret Imperial plans and transmitted them to her ship. She feigns ignorance and protests to Vader that she is a member of the Imperial Senate on a diplomatic mission to the planet Alderaan, but Vader doesn't believe her and orders her taken away. Vader's adjutant aide, Commander Jir (Al Lampert), insists that holding her captive is dangerous; news of her captivity would generate sympathy for the rebellion against the Empire. Vader instructs Jir to deceive the Senate and permanently erase any trace of Leia's whereabouts by faking her [accidental] death. Upon being notified by another officer that an empty escape pod was jettisoned during the firefight, he concludes that the Princess hid the stolen plans in the pod

C-3PO and R2-D2 land on the desert planet; R2-D2 mentions a mission to deliver some plans, but C-3PO is more concerned with staying in one piece long enough to find civilization. The two split up, and both are eventually captured by a group of diminutive scavengers called Jawas. The Jawas are junk traders, and R2-D2 and C-3PO are their newest assets. Meanwhile, a unit of Imperial Sandtroopers find the crashed pod and discover droid parts and tracks leading away from the crash site.

A huge firefight ensues in the corridors of the Rebel ship, with many Rebel soldiers being lost in the battle. When the smoke clears, Darth Vader (David Prowse; voice: James Earl Jones), a man dressed in a black cape, black armor, and a black helmet that obscures all his features, briefly surveys the damage before interrogating the ship's captain, who claims that the ship is on a diplomatic mission to the planet Alderaan. Vader perceives that he is lying, noting that a consular ship would have an ambassador on board. (In actuality there is a diplomat aboard — Princess Leia Organa — but she is hiding from Vader, the second-ranking man in the Empire, which tends to support Vader's thesis that somebody on this ship is up to something.) Upon learning that "the plans" were not downloaded into the ship's computer, Vader strangles the captain. He then tells the troops to search the entire ship and to bring all the passengers to him — alive.

Following the opening crawl, the frame moves down in the star field and we see a pitched battle between two starships in orbit around the desert planet of Tatooine. A small Rebel blockade runner, the Tantive IV, is being pursued by a mammoth Imperial star destroyer, the Devastator. Inside, protocol droid C-3PO (Anthony Daniels) and utility droid R2-D2 (Kenny Baker) are tossed about as their ship endures a barrage of laser bolts, and "3PO" concludes that escaping capture will be impossible. The Rebel ship is so heavily damaged that its main power reactor must be shut down. It is caught in the Imperial destroyer's tractor beam, pulled into the hold of the larger ship, and boarded by stormtroopers from the Empire's 501st Legion.

Weeks later Indy and Marcus feud with the Army officers over the whereabouts of the Ark, Indy angry that the Army has no idea what it has in the Ark -- though it appears they in fact do understand what they have, as the Ark is sealed in a large crate and stored anonymously in a gigantic government warehouse, never to be seen again.

At an elaborate ceremony atop the mountain Indy and Marion, tied to a pole, can only watch as the Ark is opened, but it contains nothing but sand, the remains of the stone tablets. No sooner is it opened, however, than its spirits suddenly appear. Indy and Marion, remembering an ancient code that requires people to close their eyes and not look at the now-freed spirits, withstand the mayhem that ensues as the energy of the Ark surges forth and its spirits attack the now-terrified Nazis, killing the entire contingent and destroying Belloq in gruesome fashion. The energy mass surges high into the sky before returning to the Ark and resealing it, leaving Indy and Marion drained but freed.

Indy has grabbed a rocket launcher and intercepts Belloq, vowing to blow up the Ark unless Marion is freed. But Belloq calls Indy's bluff, knowing Indy wants to know what the Ark contains as much as anyone. Indy finds he can't carry out his threat, and is seized.

He and Marion board a ship taking the Ark back to the US, but a Nazi submarine captures the ship. The Ark is taken aboard the sub and Marion taken prisoner for Belloq. Indy, however, escapes Nazi pursuit and rides the submarine as it sails on the ocean surface to an island where Belloq and the Nazis trek to the top of a mountain.

Dietrich orders his men to transport the Ark by truck to Cairo. When Sallah finds Indy and Marion, he is overjoyed they're alive and tells them of Dietrich's plan. Indy takes a horse and pursues the convoy, seizing the truck containing the Ark and surviving a brutal chase and fight with Nazi soldiers to drive the Ark to safety

Indy notices a wall where snakes are entering. He climbs a mammoth statue and with all his might breaks it from its foundation and it crashes through the wall. The two find an opening to the surface, and discover the airfield at the excavation camp, where there is a bizarre Nazi transport plane. The two sneak up to the plane, but Indy is attacked by a mechanic and a prolonged fight ensues that is joined by a burly Nazi who pummels Indy before being punched backward and shredded to bits by the plane's propellers. Marion seizes one of the plane's machine guns and opens fire on Nazi soldiers, in the process setting a fuel dump aflame. The fire destroys the area and the plane explodes, but Indy and Marion escape.

In the spring of 1936 an exploration party penetrates thick jungle on the South American continent. When the group's leader stops to examine map fragments, another of the group pulls a gun. The leader, hearing the click as the turncoat chambers a round, pulls out a bullwhip and disarms the man, sending him fleeing back through the jungle. The man who expertly wields the bullwhip is Dr. Henry "Indiana" Jones, Jr. (Harrison Ford), an archaeologist with a reputation for heavy-handed field work that takes him around the globe in search of ancient treasures.Indy and his remaining companion, Sapito (Alfred Molina), enter a dank and oppressively vast cave, where a competitor of his, Forrestal, disappeared. Inside the cave are several traps rigged by the ancient people who hid a small, valuable statue there -- and one of the traps is found to have snared Forrestal. Jones finds the antechamber where the statue sits atop a pedestal and is protected by an elaborate system of pressure-sensitive stones that release deadly darts from the surrounding walls. Jones avoids the booby-trapped stones and makes it to the idol. He very deftly replaces the idol with a bag of sand, judging the weight of the treasure by sight. However, the weight is not precise, the pedestal sinks and the chamber begins to disintegrate. Jones runs, narrowly avoiding the darts. When he arrives at a bottomless pit he & Sapito had crossed earlier using Jones' bullwhip, Sapito crosses safely but refuses to give Jones his whip unless he gives him the idol. Sapito drops the whip and runs off. Jones manages to jump across and pull himself up and escape under the stone door that closes. He finds Sapito dead, killed by the same trap that killed Forrestal. Jones retrieves the idol and must once again flee while a large boulder rushes toward him.Seemingly safe, Indy is cornered by the Hovitos, the local tribe, who are led by Dr. Rene Belloq (Paul Freeman), an arrogant French archaeologist who is a longtime rival and enemy of Indy's. Indy flees and is rescued by Jock (Fred Sorenson), flying a seaplane, though Indy isn't pleased to find Jock's pet snake Reggie inside

Indy flies to Nepal (followed by a Nazi agent, Toht (Ronald Lacey)) to confront Marion Ravenwood, who runs a restaurant and bar (and who can outdrink anyone) because he needs the headpiece to the Staff of Ra, whose crystals will allow him to determine the exact location of the Ark. Marion, still bitter over their breakup, nonetheless accepts when Indy offers her $3,000 and the promise of more when they return stateside. She is cryptic about the headpiece, and after Indy leaves she ponders it as she wears it around her neck.

Toht and several Sherpa heavies enter the bar and hold Marion hostage, with Toht ready to torture her for the headpiece. Indy returns and a firefight erupts during which the fireplace is dislodged and the building begins burning down. Toht finds the headpiece but when he grabs it he's badly burned -- leaving an image of one side of the headpiece branded on his hand. He escapes while Indy and Marion do likewise and fly to Egypt to see Indy's pal, Sallah (John Rhys-Davies), who is working on the Nazi site and who reveals that the Nazis are aided by a French archaeologist (Belloq).

Later, while shopping at a Cairo bazaar, Indy and Marion are attacked by sword-wielding Arabs working for Nazi agents. Indy fights them off but in the confusion Marion is trapped in a large basket and taken by two of the terrorists. The effort to track her down is held up by a man brandishing a sword in intimidating fashion. The swordsman is shot down in short order by a thoroughly unimpressed Indy.

Late that afternoon Indy and Sallah sneak a digging party of their own to the actual location of the Well of Souls. Late into the night they dig open the chamber, and to Indy's horror it is filled with dangerous snakes. Indy clears an area of snakes with burning torches, then lowers himself into the chamber and burns many of the snakes alive with flaming gasoline. Sallah follows and the two eventually find the gigantic chest that is the Ark.

By now it is dawn, and only now does Belloq notice the commotion a mile away. The Nazis surround the site and Indy is left trapped inside, but Dietrich leaves him with something else -- Marion, who is thrown into the chamber and the area closed off.

Infiltrating the mammoth site, Indy is lowered into an underground maproom containing a precisely detailed miniature of the city. Using the Ra headpiece, he identifies the precise location of the Well of Souls. Sneaking further around the gigantic camp, Indy is shocked to find Marion, alive but bound and gagged. Indy starts to free her, but when she reveals that the Nazis keep asking about him and what he knows, he realizes he can't cut her loose without revealing his presence to the Nazis.

Sallah takes Indy to see a shaman who is reading the Ra headpiece after both men have learned that Belloq and his Wehrmacht aide, Colonel Dietrich (Wolf Kahler), have obtained a copy of the headpiece. (Neither man is aware that it is a duplicate traced from Toht's burned hand.) The shaman reveals two critical facts: first, that the headpiece gives the precise height of the Staff of Ra, and second, that the staff the Nazis used was too long -- so their excavation is over a mile away from the Ark's actual burial site, which is known as the Well of Souls.

Soon Indy spots a basket carried to a truck filled with explosives and is fired on by a submachine-gun-wielding assailant. His Nazi commander orders the Arabs to take off, but Indy shoots them and the truck crashes, exploding and destroying the basket.

Disconsolate over losing Marion, Indy drowns his sorrows in drink but is met by more Nazi agents who escort him to a table at which is seated Belloq, who gleefully talks about finding the Ark. Indy, no longer caring whether he lives or dies, reaches for his sidearm as Arabs inside pull rifles -- only to see Sallah's large brood of children rush in and the "Arabs" to turn out to be US Marines, much to the embarassment of Belloq.

Back stateside, Indy teaches an archeology class and is still upset over the loss of the statue, which he surmises Belloq is taking to Marrakesh; he has found pieces he feels will pay for a trip to Marrakesh to find Belloq, but Indy's friend Marcus Brody (Denholm Elliott) dashes that hope by informing him that two Army Intelligence officers want to talk to him about Abner Ravenwood, his former teacher, who was his friend until Indy broke up with his daughter, Marion (Karen Allen).The Army officers are concerned because they've intercepted a German cable concerning a mammoth archaeological dig in the Egyptian desert. When they read the cable, Indy and Marcus realize the Nazis have discovered Tanis, an ancient city buried in a gigantic sandstorm in 980 B.C. and the possible burial site of the Ark of the Covenant. The Ark was built by ancient Hebrews to hold the stone tablets on which Moses inscribed the Ten Commandments. It holds immense mystical power -- enough to allow the Nazis to level mountains and lay waste to entire regions.