Unending

"Unending" is the twentieth episode of the tenth season of Stargate SG-1 and is also the series finale of the entire Stargate SG-1 series.

Synopsis
The Odyssey travels to Orilla upon the request of the Asgard who then offer to upgrade the Odyssey before their mass suicide. However, three Ori warships soon arrive. After jumping through hyperspace attempting to lose the Ori warships their shields eventually fail, and their only chance to save the ship is to activate a Time dilation field, wherein SG-1 remain trapped for fifty years, whilst Carter attempts to develop a solution or escape to their predicament.

Plot
The Asgard contact Stargate Command to tell them to rendezvous at the Asgard homeworld because they have news of great importance to share. During the boring journey Vala Mal Doran arranges a surprise birthday party for Dr. Daniel Jackson, to which he responds with annoyance — since it is not his birthday (and she is only trying to alleviate her own boredom).

When they arrive at the Asgard home world of Orilla they are greeted by Thor who announces that the Odyssey will be given a complete copy of the Asgard's latest technology. Thor explains that the Asgard's final attempt to fix their inherent gene degradation was a failure again, and as a result the entire Asgard race has contracted a terminal illness. The damage from years of such experiments is so severe that they are also no longer able to ascend. However, rather than allowing themselves to slowly die out and have their technology plundered, the Asgard people have decided to give their most sophisticated technology and their entire knowledge base to the Tau'ri, the only race they trust enough to do so, whom Thor finally calls the "fifth race", before they will all commit an act of mass suicide.

As the final installations are completed, three Ori warships exit hyperspace and attack Odyssey. The Asgard beam off the ship, and Odyssey flees. One Ori ship follows, the others turning on the Asgard. However, the Asgard destroy their own planet, wiping themselves out. With the Odyssey's shields damaged and the hyperdrive temporarily unusable because of the planet's destruction, Landry orders that they come about and use the new, as of yet untested by them, Asgard plasma beam weapons. This succeeds in penetrating the shields of the Ori warship and destroying it, much to Landry's relief and pleasure with Mitchell remarking, "We got 'em".

After entering hyperspace, Lt. Colonel Samantha Carter discovers some strange readings from the new hyperdrive system, and suggests that they stop using it. Immediately after exiting hyperspace, two more Ori warships emerge. After quickly re-entering hyperspace, Carter realizes that the Ori warships are tracking the energy signature of the Asgard computer core, which has been interfaced with all of Odyssey's systems. With no alternative, Landry orders them to head for the nearest planet with an active Stargate and off-load Odyssey ' s crew.

As soon as the crew including Major Kevin Marks are all beamed off, SG-1 and Landry remain on board as Carter tries to disconnect the hyperdrive from the Asgard computer core, which she hoped would prevent the Ori from tracking the ship. The process is time-consuming, and the Ori ships quickly catch up to resume the attack. Odyssey takes several beam shots to the shields causing increasing reflexive damage, and Landry orders that Odyssey ' s fire be concentrated on only one target with Mitchell steering the ship while attempt to shoot at the same time as Daniel monitors the ship's status. The Asgard energy weapons penetrate the Ori warship's shields, inflicting serious damage. Odyssey's shields fail as a final beam is sent out by the remaining Ori ship. However, just before the beam makes contact which will no doubt result in the deaths of SG-1 and Landry along with the Asgard technology being lost forever, Carter activates a time dilation field around the ship — one of the new integrated features of the Asgard technology.

Within the time dilation field, time passes in such a way that years may go by within the field while fractions of a second pass by outside in 'real' time. Safe for the time being, to everyone's surprise and relief, Carter is able to work on several theories to allow the team to leave Odyssey before the beam hits, or to jump the ship out of phase before the beam makes contact. However, all of her simulations produce the same result: the destruction of the ship, the death of all on board, and the loss of all of the Asgard's knowledge. Stuck until they are able to figure out a new solution, SG-1 prepares for a long wait. With a Zero Point Module and the Asgard power core to power the time dilation field and the new Asgard technology synthesizing food, supplies and oxygen, they are at least able to live on the ship indefinitely. However, not everyone's amused by this, firmly believing they're all going to go stir-crazy soon enough (especially Mitchell and Vala).

During their initial months on board, Vala repeatedly tries to seduce Daniel, while he continues to repel her advances. Finally, after three months, Vala gets even more direct and attempts to remove Daniel's pants. Daniel rejects her point blank, and angrily confronts Vala for what he believes to be her insincerity, teasing, and mocking of him. He says they could never have a serious romantic relationship, that he couldn't even imagine them having one, and did not believe she ever thought of them seriously having a relationship. Vala, who's in fact always had a very sincere 'soft-spot' for him, is greatly hurt and upset by his words, and attempts to hide her face while tears stream down her face. When Jackson sees the sincere tears and the true depth of her feeling, it finally makes him realize that she really does care for him after all and was actually being sincere. So he gently turns Vala's face towards him, looks deep into her eyes, and plants a kiss on her lips. They finally share a passionate embrace. The next scene sees a somewhat disheveled Vala leaving Daniel's cabin as Mitchell jogs past, seemingly nonplussed at the sight.

Vala, exasperated and energised (and seemingly quite elated with the turn of recent 'romantic' events), volunteers to help Carter, hypothesizing that they could reverse time in the field up to the point they left the Asgard home world, and then disable the hyperdrive. Sam however rules this out as impossible, and attempts to explain that's not how things works within the dilation field.

Years pass, as each member of the team attempts to deal with their isolation. Landry develops a gardening hobby, as the plants shoot up around all around him; Carter finally learns how to play the cello, something she's always wished she had time to learn; Daniel continues to work on translating information in the database and continues with his never ending studies; Teal'c and Mitchell spar with each ever more vigorously, as always; and Daniel and Vala develop their romance, falling cushily into an easy and comfortable relationship. Mitchell also spends much time jogging throughout the ship, growing more frustrated and angry as the years pass him by. Scenes show him wrecking his cabin, and sitting staring longingly in a F-302 fighter-interceptor, contemplating escape (which would be followed by quick death). In another scene, Daniel holds a frustrated crying Vala. After many years, Landry succumbs to old age and dies. Teal'c however, having an extended lifespan, changes very little, except for a small gray streak in his hair.

After fifty years, with everybody besides Teal'c aging greatly, Carter finally figures out how to reverse time within a localized field. By reversing time back to slightly before the point of dilation, they can stop the program being activated and use a new program Carter has written onto a crystal to quickly disconnect the Asgard computer core from the hyperdrive in seconds. Unfortunately, in a last cruel irony, the ship's power supplies no longer have enough energy to complete the plan, due to the constant drain of maintaining the time dilation field over all the last five decades.

However, Mitchell directs Carter's attention to the Ori energy beam weapon; he theorizes that by deactivating the dilation field and allowing the beam to hit, they can channel the beam's power to the core. If it indeed works, the dilation field would reverse, and they would go back in time; everything would be undone. However, there are two problems. First, the ship will be destroyed by the blast, and if the time reversal does not activate quickly enough, the destruction will not be reversed, killing everyone in the process. Second, the reversal of the time field will mean the loss of any memories of what happened over the past fifty years. Also, one person will have to remain behind, protected within a separate field, staying aged so as to retain the memories necessary to perform the rescue attempt. Teal'c, who as a Jaffa has a much longer lifespan than the other members of the team, volunteers as the only logical choice. As the group prepares their plan, Vala and Daniel exchange a last embrace, assuring each other of the sincerity of their love and that it was not just oportune. When everything is in place, they deactivate the time dilation field, and...

As the ship explodes around Teal'c, time begins to slow, stop, then slowly starts to reverse. The ship re-forms, the beam withdraws, and time is re-set to the moment just before they would've been hit. Teal'c prevents Carter from activating the time dilation field much to Carter's amazement and gives her the control crystal that disconnects the Asgard computer core from the hyperdrive. They leave before they are destroyed, saving themselves as well as the Asgard's legacy.

Back at the SGC, Teal'c refuses to reveal any of the events on the ship to the others, much to Vala's disappointment and frustration. She's convinced that over all that time she must have hooked up with someone, and is desperate to find out who - all her guesses incorrect, and unconfirmed by Teal'c. However, Daniel jokes that Teal'c did reveal to him several bits of good advice that Daniel read in the Asgard database in the alternate timeline, but they're really just common aphorisms. SG-1 contemplates these words of wisdom — among them "life is too short"—as they prepare for another mission.

As the episode—and the series—comes to a close, the team says "Indeed" all at once, Landry wishes the team God-speed.

With that, SG-1 steps through the gate on their next mission.

Notable Quotes
Jackson: I told you to bring something to amuse yourself. I didn't mean me. Or the crew.

Vala: They won't believe that it's my birthday. Again.

Jackson: Not my problem.

Vala: Being stuck on this ship is worse than being stuck at SGC. I tell you last time I was this bored I took hostages.

Jackson: I was there.

Thor: As a race, we are dying. Very soon, we will all be gone.

Carter: I promise we will do our very best not to let you down.

Thor: You are the Fifth Race. Your role is clear. If there is any hope in preserving the future, it lies with you and your people.

Carter: No pressure, huh?

Thor: You have earned my respect and my friendship.

Carter: The feeling's mutual.

Jackson: I mean, all they wanted to do was live a little longer. We're no different. Sequence DNA. Cure diseases. One fatal mistake, and they doom their entire race. I guess no matter what you do, at the end of the day…life is too short.

Thor: My only regret is that our physical weakness have left us not being able to help you any further.

(Sam hugs Thor)

Vala: (To Daniel, about the prospect of being stuck on the ship, in a small whisper) I'm going to go crazy.. and I'm taking you with me.

Landry: (To Crew, about the possibility of spending a long time in the time dialation field) Bottom line is, none of you are going to have any excuse for being behind on your paperwork.

Jackson: Yes, you've proven yourself to be trustworthy on a professional level, and for that, I am very proud of you, but on a, on a personal level? Vala, come on, give me a break! I mean, at best, you're an emotional, unstable wreck. I'm not saying I'm much better. I'm not saying I'm much better.

Jackson: Beggars can't be choosers. Better late than never. Look before you leap.

Mitchell: The best things in life are free.

Vala: Let me guess, beauty is only skin deep.

Jackson: Silence is golden.

Mitchell: Jack of all trades, master of none.

Carter: Nothing ventured, nothing gained.

Vala: Life is too short.

Teal'c: Good things come to those who wait.

Mitchell: Just another everyday mission to save the galaxy sir.

Everyone: Indeed.

Deaths

 * Thor
 * Kvasir (implied)
 * Aegir (implied)
 * Freyr (implied)
 * Hermiod (implied)
 * Loki (implied)
 * Asgard Race
 * This excludes the Pegasus Vanir.

In other languages

 * French: Le Temps d’une Vie (The Time of a Life)
 * Hebrew: Nitzchi (Unending)
 * Italian: Senza Fine (Unending)
 * Spanish: Interminable (Unending)
 * Czech: Bez konce (Without End)
 * German: Endlosigkeit (Endlessness)