Battle of Antarctica

"If the Tau'ri possess the weapons of the Ancients, we shall see."

- Anubis

The Battle of Antarctica took place in the air above the continent of Antarctica on Earth between Humans, using X-302 fighters and the Prometheus (X-303), and the forces of Anubis.

Background
Having learned of the existence of one of the Ancient's repository of knowledge on P3X-439, SG-1 went there to acquire the information, hoping to locate the Lost City. When they learned the Goa'uld System Lord Anubis was on his way, Colonel Jack O'Neill decided to destroy the device. Daniel Jackson tried to have knowledge downloaded into his brain, but O'Neill stopped him, having it downloaded into his instead, as well as destroying the device. Anubis, upon learning this, decided to attack Earth. SG-1 returned to Earth, only to discover that General George Hammond had been relieved by the newly inaugurated President Henry Hayes, at the urging of Vice President Robert Kinsey. Hammond's replacement, Doctor Elizabeth Weir, was swayed allow SG-1 to take a tel'tak to travel to Proclarush Taonas. There, O'Neill activated an Ancient Star Map, bringing up a hologram of Earth and saying two words in Ancient: Terra Atlantus. The Lost City of the Ancients is the Lost City of Atlantis, and it was on Earth. Daniel and Samantha Carter were dumbfounded to have travelled here, but O'Neill also revealed that he needed a ZPM.

Battle above the ice
Anubis sent three ha'taks that destroyed a naval battle group. After that, he appeared in the Oval Office, using Asgard hologram technology, and demanded Earth surrender to its "god". Hayes refused to be intimidated, and Anubis brought another thirty plus motherships with him, including one of his super motherships.

O'Neill, having modified the engines with the help of Carter to get them to Earth in time, also modified the Ring transporters to burn through the ice of Antarctica, which is where Altantis was supposed to be. They relayed their information to Earth, asking for help to succeed. While Kinsey tried to relieve Weir of command, Hayes "accepted" Kinsey's resignation, and sent the Prometheus under the control of Hammond to assist. The fleet of F-302s, lead by Lieutenant Colonel Cameron Mitchell, was able to arrive quick enough to provide cover fire, while the Prometheus acted as a shield against potential orbital bombardment. Mitchell himself shot down an al'kesh trying to attack the tel'tak, but was soon shot down himself.

Finally, Anubis' mothership was in place to attack the Tau'ri. Hoping to buy them time, Hammond ordered the Prometheus to ram the mothership. SG-1, meanwhile, rigned into the Antarctic outpost. Anubis's sensors had also located the outpost, and he sent a hologram of himself there to taunt them. Kull warriors then rinned down to secure the base. SG-1 covered him, O'Neill replaced depleted ZPM in the platform with the ZPM taken from Proclarush.

The power of the Ancients
"NOOOOO!"

- Anubis before his ship was destroyed

In the end, O'Neill was able to access the outpost's defensive system via the control chair. Thousands of Drone weapons were launched, which easily pierced the shields of the Goa'uld fleet. Anubis' mothership was among those destroyed, presumably taking the System Lord with it. However, to save his life, SG-1 was forced to put O'Neill into an Ancient stasis pod.

Aftermath
After seeking the Asgard's help in erasing the Ancient knowledge (and after building a disruptor which would destroy the Replicators) O'Neill was promoted to Brigadier General and made commander of the SGC, while Samantha Carter was promoted to Lieutenant Colonel and made commanding officer of SG-1. General Hammond was appointed to head the Office of Homeworld Security, which would oversee the SGC, Atlantis military contingent, and the X-303.

Dr. Weir was appointed head of the research team that studied the Antarctic outpost. After learning that Atlantis headed for the Pegasus galaxy, she petitioned O'Neill to lead an expedition to the Lost City. O'Neill agreed, and the Atlantis Expedition was launched using the ZPM found, which depleted it.

Though Anubis survived, and briefly took Hosts by moving from people stationed in the SGC, he was presumed dead. Having been the dominant force in the Goa'uld Empire for two years, his disappearance was almost as chaotic as the death of Ra. To avoid the war that followed the deaths of Apophis and Cronus, the System Lords divided his territories, but Ba'al was able to learn the location of the Kull warriors, and took control of them. Baal eventually conquered the rest of the System Lords, though he was defeated in the Battle of Dakara.

Lt. Col. Mitchell lost the ability to use his legs for a short time, but with physical therapy, he regained the ability to walk. After returning to active duty, a year after the battle, he asked to join SG-1, only to learn that he would form a new SG-1, having learned the other members had move on to new projects in the wake of fall of the System Lords. Eventually, Mitchell was able to reunite the members.