Unnatural Selection

"Unnatural Selection" in the twelfth episode of the sixth season of Stargate SG-1.

Synopsis
After retaking the new ship Thor asks SG-1 for their help in defeating the Replicators once and for all, since the Replicators have taken over Hala and have taken Human form. The only way to ensure the success of taking them down is to trust Fifth, one of the Replicators.

Previously on Stargate SG-1
SG-1 discovers the android Reese, the creator of the first generation of Replicators and send her to the Asgard for study. The Prometheus is stolen by rogue NID agents and taken into hyperspace. SG-1 manages to retake the ship but are stranded. Thor arrives and requests their assistance as the Replicators have invaded their homeworld.

Plot
Thor, who has rescued SG-1, informs them that he needs their help to defeat the Replicators and because the Prometheus isn't very advanced (compared to Asgard standards), they could fly unchallenged into Replicator-controlled territory. In addition, he informs them that the Asgard were able to call all Replicators back to one point, their first colony world, Hala, by using a signal found in the android Reese. They then tried trapping them using a time dilation device, in a sphere encompassing the entire planet, but their plan ultimately failed. If they are allowed to escape, they will conquer the Asgard and most likely be drawn to the Milky Way and Earth's raw materials. Now he wants SG-1 to solve this problem but Colonel Jack O'Neill is by no means interested in this operation. Thor brings them back to Earth, where he beams up supplies from Stargate Command and transports extraneous passengers off the Prometheus, except SG-1, to the planet.

Jack later uses a holographic communicator to contact Major General George S. Hammond and briefs him about the situation. Afterward, he talks with Major Samantha Carter about the Asgard plan and then goes to the cargo bay to eat something, where he meets Jonas Quinn and Teal'c. They talk about the Replicator threat then feel themselves losing speed. Thor tells them that they have reached their target but the time-dilation device has long since been changed so that time now passes faster within the field ("by a factor of ten squared," as Thor explains). Thor wishes them luck and departs. SG-1 flies near Hala, is scanned by a Replicator patrol ship, and enters the atmosphere of the planet. They land on a large surface with only one construction, the one spot on the planet that breaks the smooth terrain. As SG-1 steps outside, it turns out that the whole ground consists of Replicator blocks. They enter the nearby building and find the time-dilation device, when suddenly a man appears. Then, four more human-like persons appear and an older man demands that Carter stop her work on the device. The groups reveals that they are in fact replicators. Upon hearing this, SG-1 opens fire on them—–with no success. Suddenly, several bug-like replicators appear and surround the team, so they are forced to disarm. The leader of the five human-form replicators offers O'Neill his hand but when O'Neill takes it, the man seemingly pushes his hand into O'Neill's head and Jack finds himself in the Gate room where the man appears. The replicator tells him that they are in O'Neill's unconscious mind. Eerily, the replicator starts to read O'Neill’s mind, including his iris deactivation code. The two go through an imaginary Stargate.

SG-1 wakes up, finding themselves back on the Prometheus. It turns out they have all experienced the same thing. In order to decimate this new threat, they plan to blow up the hyperspace engines. However, when they go to execute this plan, they meet one of the human-form replicators, who calls himself Fifth. He tells them that they are invited for meal with the other human-form replicators. SG-1 quickly returns to the building and First tells them about their history and construction. First explains that, instead of the larger replicator blocks, they consist of microscopic cell units. First also tells them that it was he who deactivated the time-dilation device and reprogrammed it. They converse about Reese and the error that embedded in her systems. First, with a condescending attitude about him, reveals that they attempted to correct the error in Fifth, yet First says Fifth is weak. Fifth is ordered to enter one of their minds and Carter agrees to. However, they enter Fifth's unconscious mind and develop a plan to repair the time-dilation device.

SG-1 awakens again with Fifth telling them that he has reconfigured the device. While Jonas and Teal'c return to the ship, Carter programs the device. However, she is secretly ordered by O'Neill to set the time on three minutes instead of the predetermined five, which they originally told Fifth to be the setting. SG-1 starts toward the ship after telling Fifth to head there himself shortly after three minutes. First suddenly appears and tells Fifth that SG-1 has lied to him but Fifth is adamant in his convictions about SG-1’s honorability. He looks at the timer and is shocked to find that it’s nearly to zero. Just as it activates, SG-1 leaves the planet. However, both Jonas and Carter feel badly that they used Fifth's "humanity against him."

Notable Quotes
Thor: The contents of your armory at Stargate Command, along with appropriate attire, food and other supplies you may require, are now being transported aboard this vessel.

O'Neill: I hope you did the paperwork.

O'Neill: Suffice to say, you might want to get upstairs and punch one on the old speed dial.

Hammond: My grandchildren?

O'Neill: Two, then.

O'Neill: They didn't go for it.

Carter: They didn't approve the mission?

O'Neill: No, they did that. Once they knew the stakes and the whole "fate of the universe" stuff. Both the President and Hammond realized we had no choice. He sends good luck, God speed, and all those things he says when he thinks we're going to die.

Carter: So what didn't they go for?

O'Neill: The name I suggested.

Carter: For the ship?

O'Neill: Yeah.

Carter: Yeah. Sir, we can't call it the Enterprise.

O'Neill: Why not?

Carter: The code name for the project is Prometheus. What's wrong with that?

O'Neill: It's a Greek tragedy. Who wants that?

Carter: Okay. The X-303 it is then.

Thor: If you wish to reconsider...

O'Neill: No, no. I full-well expected the other shoe to drop eventually.

Thor: We can only hope that this will be the last footwear to fall.

O'Neill: What is with you people? Time machines are nothing but trouble. Even we know that!

First: Your mind is incredible.

O'Neill: Well...

First: Such chaos, and humor, and pain.

Goofs

 * Calculating the time it would take to leave the 0.16 light year radius of the time dilation field at the top speed of 110,000 miles per second (as Carter stated), it would take them approximately 100 days flat out to get to a safe distance from the planet and not be affected by the time dilation field.

Nominations

 * Nominated Leo for "Dramatic Series: Best Director" (Andy Mikita)
 * Nominated Leo for "Dramatic Series: Best Visual Effects" (James Tichenor, Shannon Gurney, Krista McLean, Karen Watson, Craig Van Den Biggelaar, Tom Brydon and Bruce Woloshyn)

Character

 * Fifth

Planet

 * Hala

In other languages

 * French: Évolution (Evolution)
 * Italian: Il Tempo Immobile (The Still Time)
 * Spanish: Selección Antinatural (Unnatural Selection)
 * Czech: Nepřirozený Výběr (Unnatural Selection)