Battle of the Stargates

Prelude
While investigating the nature of an addictive corn-like crop grown on an alien world, found by accident by SG-3, SG-1 gets into a firefight with members of the Lucian Alliance. After SG-1 retreats to the gate, Daniel tries to dial out only to have the gate beamed off world before he can finish. Having nowhere to retreat to, SG-1 is captured and Worrel, leader of the local Lucian Alliance faction, suspects them of the theft. Meanwhile on Earth, General Landry learns from the Tok'ra that someone has been stealing Stargates all over the galaxy. He suspects Ba'al but needs proof and turns to the imprisoned former follower of Ba'al, Nerus. At the same time, the newly-commissioned Odyssey is dispatched to rescue SG-1. Nerus confirms Landry's suspicions and tells him that Ba'al is likely trying to establish a new empire with the gates. Following a sizable feast provided by Landry, Nerus admits to have developed a way to disable a Stargate's correlative update program, effectively rendering one undetectable to the network. Baal's plan was to set up his own network of Stargates on his own planets, then use the Dakara device to wipe out the rest of the galaxy using the original Stargate network.

The Battle
Meanwhile on the alien planet, Worrel is about to execute SG-1 when they are beamed aboard the Odyssey and filled in with the latest information on Ba'al's scheme. Nerus requests his freedom in exchange for the coordinates to Ba'al's location, but Landry is reluctant to accede. As he knows better than to trust a Goa'uld, Landry secretly feeds a subspace locator beacon to Nerus and then agrees to release him. When Nerus finally returns to Ba'al's ship, the beacon transmits his position to the Odyssey. When trying to use his technology with Ba'al's ship, a virus created by Dr. Lee executes, disabling the ship's defences and rendering it blind to the arriving Odyssey. SG-1 beams aboard the ship, makes its way to where the stolen gates are stored and begins planting locator beacons on them so they can be detected by the Odyssey.

Not everything goes smoothly as the Lucian Alliance detected Ba'al as well, and three Ha'taks begin firing on Ba'al's defenseless vessel. Ba'al quickly manages to restore his shields, preventing Odyssey from beaming out SG-1 and the final gate. With Jaffa closing in, SG-1 uses the last gate to return to Earth. Soon after, Ba'al's ship is destroyed and the Odyssey, not battle-ready, escapes when the Lucian Alliance vessels target them.