The elderly Colonel Young from the alternate timeline lies ill while Chloe sits with him. Young's son Steven arrives and says that Sara will be there for a few minutes.
In the present, Scott and Greer land the shuttle and the party emerges to find ash falling from the sky. They call Destiny and report that they haven't found anything. Yaozu has pointed out a possible shelter, but the doors are proof against C4 and the shuttle's weaponry. Brody suggests they use 60% power, and Eli and Rush concur. Once they fire the weapons, Scott confirms that they've gained entrance. Yaozu leads them to an elevator which takes them to the Teneran archives.
The team reviews the kino footage of their alternate selves arriving on Novus two thousand years ago. Eli establishes communications with Destiny and Rush insists that they need to focus on survival. Scott confirms that there are stores in the shelter and Young sends Rush to check out the archives.
On the video footage, the Destiny survivors discover the air on the planet is too thin and try to find a planet within range to dial to.
When he arrives, Rush immediately goes off on his own.
Greer and Scott find a planet that can sustain them.
As the scientists go over the archive records, Yaozu isn't thrilled that Brody is accessing the computers, since he was the founder of the rival nation. As a "founding father," Eli volunteers to help.
The crew wonders when Rush will return, and Young says they can't just wait and orders them to build shelters and find foods.
Rush checks in on Scott and Greer, who are looking for supplies. Scott reports to Young that the scientists are trying to find a way to upload the data to the ship. Chloe finds thousands of books written by Eli, and her own diary.
The ship's crew builds shelters, and Brody and Eli argue about where to set up their first settlement. Brody wants to move to a nearby plain, and points out that it was Eli's calculations that lead them to the planet, and Young interrupts them to insist that they stay where they are. Scott says that they need to build fences to keep out the wildlife so they can conserve ammunition, and Young agrees.
A planetquake shakes the shelter, cracking open one wall. Scott calls down additional teams to bring down supplies.
Camille is planting a garden when Volker collapses. Without the equipment that they used in the alternate timeline, Volker dies from kidney failure, and the crew holds their first funeral.
Volker reads the archive entry on his death as Camille arrives to tell them they need him on Destiny to begin the uplink.
Johansen checks on Yaoku, who was injured in the quake.
Johansen tends to Young's injury and notes that he's working too hard. Varro checks in and Johansen advises him to take it easy while working. He walks off and Johansen finishes her stitching, and then assures Young that no one blames him, and they need to make the most of their new home. She tells him not to beat himself up, and then they kiss. Varro watches from nearby.
Eli confirms that the planet's Stargate was destroyed decades ago in a lava flow, and both countries worked together to pool their resources and build evacuation ships. The two countries then departed but it will take them hundreds of years to arrive at their new planet at slower-than-light speed
Scott tries to talk to Vanessa, explaining that he usually tries to sabotage relationships. She tells him that he should be proud of himself, and insists that she won't miss his marriage. Young presides over the wedding ceremony of Chloe and Scott, while a pregnant Johansen looks on. Varro and Vanessa smile at each other.
Eli watches a recording of his alternate self talking about how everyone is hooking up expect him and Brody. Meanwhile, the scientists prepare the upload and Park locates an incomplete evacuation ship stored nearby.
Eli records a pregnant Chloe, and assures her that Matt will make a great father.
Park discovers that a black hole has entered the system and the gravitational forces are ripping apart the planet. Brody warns that the upload is nowhere near complete, and Eli calculates they only have 37 hours to upload all of the information.
Johansen arrives as Chloe goes into labor. Johansen then has a son with Young. Later, Park gives birth to her son and Greer's, and they name the child Dale. Johansen and Young have two. Eli soon marries Corporal Barnes, and she has a child of his own.
Eli watches the videos of his alternative self and is surprised to learn that he ended up with Barnes.
Rush goes through the supplies and finds grey stone-like materials. He's interrupted when another quake shakes the shelter. They reported to Young and warn that the fault line beneath the city is getting larger. Scott assures the colonel that they're keeping an eye on it and the shelter should be able to withstand the worse of it for now.
Camille is working in her garden and tells Chloe and Johansen that she's already found her soul mate, and isn't interested in finding someone else. Johansen rushes to keep her son from getting hurt and feels a pain in her wrist.
Scott tells Young about the partially completed evacuation ship and prepares to take a party to check it out. Rush arrives and tells Scott to fly him to Destiny afterward.
Johansen watches a recording of her past self, describing symptoms which she confirms signify ALS: Lou Gehrig's Disease. Later, Varro gets word of her alternate self's disease and tries to reassure her, but Johansen says that there's no cure and the disease is genetic so she can't avoid contact with it.
Scott flies the shuttle to the ship manufacturing factory only to discover it's been swallowed by lava.
When Young gets word of Johansen's future disease, he comes down to see her and report that Volker is looking for a cure in the Ancients' database. Johansen tells him that according to the logs, she dies in five years. Scott calls to report to Young what they've discovered, and wonders if they can take the Tenerans back onboard given their lack of supplies. Rush tells him not to worry about it. Young orders everyone back onboard, and then moves to comfort Johansen, who breaks into tears.
Young watches as his wife slowly die, helping her where he can as their children grow up. Finally she passes away.
Eli warns that they've only uploaded a third of the database, but Young orders everyone back to Destiny. Another quake shakes the planet and Young tells them to go. Yaozu tells Johansen that they discovered a cure for her affliction and many more, and they're all in the Teneran archive.
Volker checks on Rush and is surprised to learn that he's returned to the ship. Rush says that he's too busy to help Volker find the cure in the database.
The various families grow older and have grandchildren, while Camille drafts a constitution and Eli teaches the children. Brody complains about all the children tearing up his lawn.
Young prepares the last team for evacuation, and Eli warns that he can't search for the information because he's compressed what he can of the remaining data, and has no idea if the cure is in the data they've already uploaded, or the information that he's compressed and remains to be uploaded. Another quake shakes the planet.
Young wins the first election as leader of the settlement, but a group decides to break away and leave the planet.
Young, Eli, Varro, and Johansen are trapped by the quake and prepare to climb up the ladder. Eli goes first and the others follow as he gets to the top. One rung breaks, dropping Johansen, but Varro manages to catch her and swing her to safety. The extra weight breaks off his own rung and he plummets down the shaft. They get close enough to the surface for Scott and Greer to lower a rope and pull up first Johansen and then Varro, who is barely alive. As they prepare to pull up Young, another quake shakes the complex as the lava closes in. They get him up and lift off just in time.
An elderly Young lies dying and apologizes to Chloe for never getting them home. Scott arrives with Young's daughter, Sara, and Chloe tells Young that they are home.
Rush installs the substance he found on the planet, a substance far more effective than lime at scrubbing the air. As the others leave, Volker asks Rush if it bothers him that everyone else got along fine without him in the alternate timeline.
In the infirmary, Johansen stabilizes Varro but warns that they can't do anything further. Eli reports that the cure wasn't in there, and they've found nothing in the Ancients' database yet. Johansen suggests that they get the information from the archives of the evacuation ship, but Eli says that they won't arrive for 200 years. He tries to reassure her, insisting that they'll find a cure from the information that their descendants accumulated.
Eli's grandson dedicates a new school in honor of his deceased father and introduces their guest of honor, the last surviving member of the Destiny survivors, Camille Wray. She talks of how they initially worried that they failed their mission, but explains that their mission was the journey itself.