The movie starts in Egypt in 1928, at a archaeological dig site where the diggers find a buried stone ring. The movie shifts to present day where Dr. Daniel Jackson is giving a lecture where he claims that aliens built the pyramids. He is laughed at and afterwords we find out that he has been fired from his teaching position He reluctantly accepts a secret job for the government. He is brought to a secret army base where he is told to translate ancient Egyptian. He instantly corrects a translation on a blackboard, after this he is shown the Stargate, which has even more symbols to translate. He figures out the symbols correspond to star constellations.
Beyond the stargate
With that knowledge they manage to use the Stargate to transport to a far away alien world. When the mechanical probe they sent stops transmitting, they send in an army team, lead by colonel O'neil and including Dr. Jackson, to investigate the alien planet. They arrive and eventually find primitive humans mining an unknown substance. They are brought back to human city where the locals are amazed at Jackson cigarette lighter, and eventually Daniel is given a women ,Sha'uri, who shows him the secret history of the humans, it turns out they are slaves taken from Egypt by aliens when they rebelled in ancient Egypt.; also proving that Jackson was correct.
At night a ship descends and covers the pyramids that the Stargate was in and contact with the soldiers is lost. O'neil and Jackson are brought into the ship where they meet the alien ruler named after the Egyptian sun god Ra. Ra is going to use the nuclear bomb that O'neil brought from Earth to make sure their wont be another rebellion and that no one can threaten his rule.
With the help of the human slaves, the Stargate team manage to beat Ra's minions, and then use the nuclear bomb to blow up Ra and his ship. With the threat gone the team starts to head home, all except for Dr. Jackson who decides to stay with the aliens to help them learn, and to be with Sha'uri, who he has fallen in love with.