In 3067 BC, the Scorpion King leads his army on a campaign to conquer the world. After fighting for seven years, his army is defeated while attacking Thebes and exiled to the desert of Ahm Shere, where his men die of heat exhaustion. After vowing to give Anubis his soul for the power to defeat his enemies, an oasis forms to hide the Scorpion King's pyramid and he is given a legion of jackal warriors in return. The Army of Anubis sweeps across Egypt, but once their task is finished, Anubis claims the Scorpion King's soul and his army.
In 1933, Rick and Evelyn O'Connell explore a ruined mortuary temple in ancient Thebes with their son, Alex, where they find the Bracelet of Anubis. And at the same time, our heroes discover a strange lightsaber, and they took it with them. And while looking at the book of Lightsabers, Sunset Shimmer says it's Master Yoda's Lightsaber! In London, the bracelet locks onto Alex, showing him a vision directing him to Ahm Shere. Alex has seven days to reach the oasis, or the bracelet will kill him when the sun's rays shine on the Scorpion King's pyramid.
Evelyn is captured by an Egyptian cult and Ernie the Giant Chicken, who resurrect Imhotep; they wish to use his power to defeat the Scorpion King, giving him command of Anubis' army to take over the world. The cult, led by Baltus Hafez, the British Museum's curator, includes a warrior named Lock-Nah and Meela Nais; the latter being a reincarnation of Imhotep's love interest Anck-su-namun. Rick sets out to rescue Evelyn, accompanied by her brother Jonathan and the Medjai Ardeth Bay.
Hafez attempts to sacrifice Evelyn but a fight ensues between Rick and Imhotep. And Ernie then feels something strong in Dawn's presences, and orders his Death Troopers to go after her. Imhotep calls on the help of mummified soldiers to kill Rick and the others. After freeing Evelyn, they flee on a double-decker bus with the soldiers in pursuit. After defeating them, Alex is kidnapped by Lock-Nah, and the Death Troopers stun and kidnap Dawn, and along with the cult travels to Egypt. The O'Connells and our heroes pursue them to rescue Alex and Dawn, along with Rick's associate from his past adventures, Izzy, a pilot, who provides the group with transportation.
While stuck with the cult, Ernie questions Dawn how she is born with the Force. Dawn acts like she doesn't know what he's talking about. And says that Ernie's just a rooster mad with power. Which causes Ernie to slap her and tells her he's planning to be the Sith king. And that he will do a better job, than anyone's ever could. And he asks her one more time that how's she's Force sensitive by pointing his Darksaber at her, but Dawn doesn't know. Which makes Ernie extinguish it and walks out the room.
The bracelet gives Alex directions to Ahm Shere that Imhotep follows and they travel there by train. At each location, Alex leaves clues for his parents, who follow in Izzy's dirigible. Imhotep uses the Book of the Dead to give Meela Nais the soul of Anck-su-namun, but by doing so he allows Evelyn to unlock the memories of her previous life as Princess Nefertiri, the bracelet's keeper and Pharaoh Seti I's daughter. Lock-Nah finds Alex leaving clues, so Imhotep makes a wall of water that attacks the dirigible, causing the O'Connells to crash into the jungle of Ahm Shere. Izzy stays with the dirigible in hopes to repair it. And then Dawn uses the Force mind trick on a Death Trooper and she escapes the cult, and this makes Ernie furious and orders them to find her. By nightfall, the O'Connells attack the cult, and both groups are attacked by pygmy mummies. Rick retrieves Alex, and Dawn bumps into Brian, while Ardeth Bay kills Lock-Nah. They escape the pygmies, who kill the cult except for Baltus. Imhotep and Anck-su-namun escape unharmed.
Rick and Alex eventually make it to the pyramid before sunrise, where the bracelet detaches from Alex's arm. Ardeth regroups with the Medjai in case Anubis's army rises. Anck-su-namun soon stabs Evelyn, killing her, and escapes with Imhotep. Rick, determined to avenge the death of Evelyn, pursues Imhotep, and Brian, Sylveon, and Dawn pursue Ernie. Baltus puts on the bracelet and revives the army. Anubis takes Imhotep's powers, wanting Imhotep to fight as a mortal. Rick finds Imhotep summoning the Scorpion King and fights him. And Ernie notices Yoda's Lightsaber, and deploys his Darksaber and tells them that lightsaber is his and Brian deploys his and Yoda's lightsaber, and so does Sylveon as Brian tells him to come and get it. And they duel him, but Ernie manages to disarm Brian of Yoda's lightsaber, as it flies to the floor. then Ernie zaps them with Force Lightning. Ernie then tries to get the lightsaber, and it seems like he'll get it but then it flies pass him and into Dawn's grip! She then activates it and then charges Ernie. The Scorpion King interrupts them, and Imhotep lies to him that Rick was sent to kill him. At the same time, the Medjai battle Anubis's army of jackal warriors. While Rick and the Scorpion King fight, Baltus is killed. Jonathan and Alex steal the Book of the Dead from Anck-su-namun and use it to resurrect Evelyn, who confronts Anck-su-namun while Alex, Jonathan, and everyone go to help Rick.
The scepter Jonathan has been carrying extends into a spear that can kill the Scorpion King. The Medjai defeats Anubis' army, but have only defeated the vanguard; the full army charges toward them. Meanwhile Dawn continues to battle Ernie as they approach the edge of the underworld, they come into a blade lock. As they are in it, Ernie then starts mono logging claiming that he can show her the ways of the Force. But after hearing that, Dawn then suddenly got a kick burst of strength and Force shoved Ernie back. And a massive battle broke out between the two. During the battle, Ernie draws fire at Dawn with his shotgun and pistol but Dawn easily blocks and deflects all his shots and then destroys his remaining guns. Then she grabs his arm and twists it, making him let go of his Darksaber. As he tried to punch her but Dawn blocked each of his shots and delivered punches and kicks of her own. And then knocks him out.
Then, Rick kills the Scorpion King, using the scepter, sending him and his army back into the Underworld, which causes the oasis to be sucked back into the pyramid. Rick and Imhotep hang above a pit that leads to the underworld. Evelyn risks her life to save Rick, but Anck-su-namun abandons Imhotep, who, heartbroken, chooses to fall to his death. Anck-su-namun, while escaping, falls into a pit of flesh-eating scarabs and is devoured. And Ernie regains consciousness, as he closes his eyes and accepts his defeat. The O'Connells and our reach the top of the pyramid, which is sinking into the desert. Izzy arrives with a modified dirigible and rescues the O'Connells and our heroes just as the oasis and the pyramid disappears completely. They depart into the sunset, with Ardeth Bay saluting them, before riding off. And Brian decides to train Dawn the ways of the Force.
- The Griffin Family, Vinny Griffin, Glenn Quagmire, Cleveland Brown, Joe Swanson, Little Bear, Duck, Cat, Owl, Hen, Emily, Lucy, Doug Funnie, Skeeter Valentine, Roger Smith, Bender Bending Rodríguez, Minerva Mink, Pazu, Sheeta, The Dola Gang, The Crystal Prep Girls, Wubbzy, Widget, Walden, Daizy, Sunset Shimmer, the Human Mane 5, Sci-Twi, Spike the Dog, Belle, Ariel, Melody, Princess Jasmine, Jenny Foxworth, Princess Anna, Queen Elsa, Snow White, Princess Aurora/Briar Rose, Alice, Mordecai, Rigby, Benson, Skips, Pops, Muscle Man, Hi-Five Ghost, Margaret, and Eileen guest star in this film.
- Ernie the Giant Chicken will work for Imhotep in this film.
- Atlantis: The Lost Empire, The Little Bear Movie, and The Mummy Returns are both released in 2001.
- The storyline concludes in Ed, Edd, n Eddy vs. The Mummy: Tomb of the Dragon Emperor.