Battle in the Alteran Home Galaxy

The Battle in the Alteran Home Galaxy occurred in 2007 between the Tau'ri, Ori, and Replicators and marked the end of the Ori crusade.

Prelude
Several months after the Odyssey received Asgard upgrades, SG-1 traveled to Dakara in search of the Ark of Truth, an Alteran piece of technology capable of bringing an end to the Ori crusade. Unfortunately, shortly after they uncovered what turned out not to be the Ark, Ori fighters and troops arrived at the planet commanded by Tomin. As he subsequently renounced the Ori and joined the Tau'ri, SG-1 and the Odyssey, commanded by Lt. Col. Cameron Mitchell, set off for the Ori Supergate and the Alteran Home Galaxy.

The Battle
The Odyssey cloaked immediately after reaching its destination in the Alteran galaxy as to not draw the attention of the Ori. However, James Marrick used the Asgard computer core to create a Replicator as part of a plan to infect the Ori fleet with them and destroy their fleet. In an attempt to destroy the Replicator, Colonel Mitchell shot it with an ARG, but the Replicator was immune to it and escaped to turn into a queen and replicate. The Replicator, as a queen, tied itself into a power conduit and started replicating a new army out of the Odyssey.

Meanwhile, teams swept the ship for the original Replicator, but by the time one was located and destroyed by Colonel Mitchell, there was already more than one. Colonel Carter started to search the program that created these new Replicators for the self-destruct that would destroy all of them at once, but four Ori ships launched an attack, forcing the Odyssey to jump to hyperspace so they couldn't be shot at while dealing with the Replicators.

The Replicators also took control of Marrick in order to get the self-destruct code so that it couldn't be used against them, and launched an attack against the Asgard Core in order to gain full control of the ship while Mitchell went to find and destroy the Replicator queen. Mitchell managed to find the queen by following the other Replicators to the cargo bay where the queen was and set up a C4 charge to destroy it as a distraction when one was needed. Marrick, controlled by a Replicator that attacked him before he could set it off, fought it out with Mitchell loosing until he pulled a Replicator attachment from Marrick's skull, causing Marrick to regain control of his body for a moment. Marrick told Mitchell where to find the self-destruct before losing control again. Mitchell blew the room up destroying the queen and Marrick, but seriously injuring himself in the process. He relayed the location of the self-destruct to Carter and she activated it just as a Replicator in the form of a human skeleton went after Mitchell. The Replicators were destroyed, saving the ship from one threat.

Meanwhile, unable to return fire, the Odyssey's shields were bombarded by Ori energy beam weapons. Despite being powered by a ZPM, it was only a matter of time before the shields would fail. After several direct hit as extensive damage, the Odyssey's shields finally failed. However, seconds before the final deadly shot was to be fired, the Ark of Truth was activated, and the Ori withdrew.

Aftermath
After the Odyssey arrived back at Earth and SG-1 used the Ark of Truth on the last of the priors, they traveled, once again through the Stargate on another every day mission to save the galaxy, knowing that they had finally defeated the Ori thus ending the Ori crusade.