In 1928, in Egypt, a strange device is found by an expedition. In the present days, the outcast linguist Dr. Daniel Jackson is invited by a mysterious woman to decipher an ancient hieroglyph in a military facility. Soon he finds that the device was developed by an advanced civilization and opens a portal to teletransport to another planet. Dr. Jackson is invited to join a military team under the command of Colonel Jonathan 'Jack' O'Neil that will explore the new world. They find a land that recalls Egypt and humans in a primitive culture that worship and are slaves to Ra, the God of the Sun. But soon they discover the secret of the mysterious "stargate".
Egyptologist Daniel Jackson is brought to an underground military base where he decodes the symbols on Egyptian cover stones as constellations. That allows an alien device, known as the Stargate, to be opened and a team led by Air Force Colonel Jack' O' Neil and Jackson to travel across the known universe to a distant planet. Arriving on the planet, they find a culture ruled by someone pretending to be the Egyptian sun god Ra. Soon, Ra captures the team and takes control of a nuclear weapon brought to the planet in case of the discovery of hostile aliens. Jackson and O'Neil escape and must fight Ra and his army of warriors to save Earth from being destroyed by Ra.
A stargate found in Egypt in the 40's is put into storage until a genius figures out how to operate it. Now, there is a link between earth and an unknown galaxy millions of light years away. Colonel Jonathan "Jack" O'Neil is sent with some men to explore the unkown but there's only one problem: When they reach this earth-like planet, there is no way to re-open the stargate without the right equipment. They must fight off evil and all to get the stargate back into its "locked" position and save the earth from the deadly bomb which is going to be sent through the stargate by the evil leader...
Blending into Egyptian myth and legend, and the covering up of an alien race that once came to this planet that took its inhabitants for slaves, not by means of ships, but the use of teleportation, and the use of the Stargate. The method of traveling to the ends of the universe, instantly, a quantum leap, from one space to another, as simply walking from one room into another, this is the purpose of the Stargate. Now, in the present day, and for eons past, the Stargate has been hidden, forgotten, and buried, as time has progressed and histories have come and gone throughout the ages; the Stargate has once more been unearthed. In the hands of the military, this portal, this unique tool, this mysterious device shall once more regenerate and transport those to wondrous and new worlds, those who now share its secret. Led by Col. Jonathan 'Jack' O'Neil, he, his team and Dr. Daniel Jackson, scientist and Egyptologist, have crossed the boundaries of time and space. These modern-day pilgrims have naively stumbled across the Kingdom of the ancient god Ra. An intelligent, cunning and malevolent aging creature that for centuries has used the bodies of his people, his slaves, his humans, to regenerate himself over and over to receive eternal life. And so in the conflict between Man and the deadly demigod Ra begins, the Stargate is where it began, and with the Stargate it shall end.
A giant structure found in the desert has studied by various scientist for nearly fifty years and are no where near discovering what it is. Until Daniel jackson, a language expert deciphers and reveals that it's a Stargate. He also discovers how to make it work. They then learn that it's some kind interstellar transport device. Now a group of soldiers led by despondent Colonel Jack O'Neill go to the planet, also accompanying them is Jackson, who said that he can reactivate the Stargate to send them back but he forgot to mention that he needs to find the symbols and they can't find anything, so it appears that they are trapped. And if that isn't enough, some aliens arrive and capture them and have nefarious plans for Earth.
An interstellar teleportation device, found in Egypt, leads to a planet with humans resembling ancient Egyptians who worship the god Ra.
The film begins in 1928, where Professor Langford discovers a massive stone ring in the sands of Giza, Egypt. In the present day, Langford's daughter Catherine offers Egyptologist Daniel Jackson, a down-on-his-luck linguistics professor, the chance to translate ancient Egyptian hieroglyphs that may prove his controversial theory regarding the Pyramid of Khufu. Jackson accepts and travels to a US Air Force installation inside Creek Mountain, Colorado. Jackson translates the hieroglyphs on the stone ring's coverstones, which read: "A million years into the sky is Ra. Sealed and buried for all time, his Stargate." Formerly retired Special Forces Colonel Jack O'Neil arrives to take command of the project and declares it classified.
Jackson deduces that the symbols are star constellations that are coordinates for a location within space. The sequence is entered into the stargate, creating a wormhole to Abydos, a planet in another galaxy. After O'Neil leads a team through the Stargate, they find themselves inside a pyramid in the middle of vast sand dunes. Jackson reveals they cannot dial home because the Stargate coordinates to go back to Earth are missing. Some team members stay at the pyramid while Jackson, O'Neil, and others go out and discover a mining village inhabited by humans who assume them to be gods sent by Ra.
Jackson realizes that the people speak a dialect of Ancient Egyptian and begins communicating with them. The team develops friendships with the people; O'Neil with Skaara, and Jackson begins a budding romance with Sha'uri, a daughter of the leader. Jackson learns from hieroglyphs in the catacombs how the Egyptian god Ra was actually an alien life form (a Goa'uld) who enslaved humans with his advanced technology. While these humans eventually rebelled and buried the Stargate, some had been taken to Abydos through the Stargate and used to mine the quartzite-like mineral on which all of Ra's technology is based. Fearing another rebellion on Abydos, Ra outlawed reading and writing. At this point, the team from Earth discovers the coverstone to get back to Earth, but the seventh symbol is eroded away.
O'Neil orders the team to return to the pyramid. A short time later, a huge spacecraft lands on top of the pyramid. Ra's general, Anubis, flanked by warriors in avian themed masks, hunt the soldiers throughout the pyramid's labyrinthine tunnels, dispatching them with blinding speed. O'Neil and Jackson are escorted to the throne room, where they meet Ra. Ra's guards unmask and are revealed to be human. Ra reveals his intention to send the atomic bomb brought by O'Neil, which was to be used to destroy the Stargate to prevent invasion by any threat, back to Earth; it is now enhanced with his quartzite-like material to produce cataclysmic results. O'Neil attempts to disarm the guards and kill Ra, but relents when Ra uses his children courtiers as human shields. Jackson is killed during the altercation. O'Neil is thrown into a dungeon with the captured team members, while Jackson is regenerated in a sarcophagus-like device. Ra states that he will kill Jackson and everyone who has seen him unless Jackson kills the rest of the team to show the villagers that Ra is their one true god.
However, once Ra has the local people gathered before the pyramid craft, several young villagers signal to Jackson that they have recovered the team's weapons. Jackson then shoots at Ra while the kids create a distraction. O'Neil, Jackson, and the rest of the team flee Ra's ship and take shelter in a cave with the boys. The next morning, when Skaara draws a picture of the people's victory against Ra, Jackson realizes that part of this drawing depicts the seventh symbol needed to reactivate the Stargate: three moons over a pyramid.
O'Neil convinces the locals that their "gods" are mere mortals and, with their help, O'Neil, Jackson, and the remaining members of the team make it back to the Stargate hoping to deactivate the bomb. When the locals begin an open rebellion against Ra's troops, Ra decides to retreat and prepares his ship for takeoff. Sha'uri is killed in the battle, but Jackson resurrects her in Ra's sarcophagus and manages to escape when O'Neil defeats Anubis and activates the ship's ring transporter. Unable to deactivate the bomb, O'Neil and Jackson transport the bomb to Ra's ship in orbit via the rings where it explodes, killing Ra. The team is able to return to Earth through the Stargate, though Jackson decides to remain on the planet.  Director's cut
The Director's cut had several scenes which were cut from the theatrical film version. The first such scene took place immediately after the excavation of the Stargate in 1928 and showed petrified Horus guards near the cover stones; the producers had tried to introduce the idea that beings had attempted to come through the Stargate after its burial, but they cut the scene for time concerns.