Revelations

"Revelations" is the twenty second episode of the fifth season of Stargate SG-1.

Plot
An Asgard ship confronts two Goa'uld Ha'taks in orbit of a planet. Thor contacts one of the ships, which is under the command of Osiris, and orders them to retreat because they are in violation of the Protected Planets Treaty. She refuses, so Thor opens fire; surprisingly, his weapons have no effect.

At Stargate Command Sam sadly looks over Daniel Jackson's belongings when General George Hammond arrives. They talk about the situation when the Stargate activates and Freyr arrives. He informs them about the Goa'uld attack on the planet and that Thor was killed. With the Goa'uld showing that they have more advanced weapons, the Asgard can no longer be certain of victory when dealing with superior numbers, and therefore none of the Protected Planets are safe, including Earth. He also asks them to rescue a scientist, who is trapped on the planet. Jack agrees to do so.

SG-1 takes a Tel'tak to the planet, and Sam talks with Teal'c about Daniel en route. When they arrive, they are beamed into a hidden laboratory. There they meet the scientist Heimdall, who informs them that Thor is still alive and imprisoned by the Goa'uld. They are able to contact him but he refuses to be rescued because Anubis will soon arrive and the Heimdall's research is too important. Heimdall informs them that the Asgard are all clones and they are suffering from genetic degradation. They then develop a plan to rescue Thor and when Anubis arrives, Jack and Teal'c transport onto Osiris' ship. With Sam's help they are able to avoid capture.

In the meantime Anubis confronts Thor with a device which will be implanted in his brain and link with the ship's computer. Later Osiris orders the coolant of the engines to be vented into the lower decks. This stuns Jack and Teal'c. On the planet Heimdall shows Sam her research work – an ancient Asgard who she's researching to find out how to make the Asgard reproduce sexually. Heimdall beams to the Tel'tak with the research while Sam remains behind.

On Anubis' ship the imprisoned Jack and Teal'c are contacted by Thor, who is able to control the ship's computer through the mental link. He opens their cell and guides them through the ship. In the meantime the laboratory is found by the Goa'uld and they use their weapons to blow a way to it so that they can transport inside it. Afterward, Osiris and some troops enter the laboratory and capture Sam.

On the ship Jack and Teal'c are able to find the control crystals for the entire ship and destroy them. Thanks to this Heimdall is able to beam Jack, Teal'c, Thor and Sam, who was questioned by Osiris, onto the Tel'tak. However because of the device in Thor's brain they are located and nearly destroyed. Suddenly three O'Neill-class Asgard ships under the command of Freyr arrive and confront the remaining Ha'tak (the other two left earlier to fight against Yu) and Anubis is forced to flee.

Back at SGC, Sam informs the others about the situation of the Asgard and Thor and that Thor fell in a coma when the device was removed from his brain.

That night, O'Neill, Carter, and Teal'c are on their way out of the base to go out to eat when there is an odd breeze inside the base. Though no one is really sure what caused it, as Jack enters the elevator he smiles.