- Harry K. Daghlian. He was a scientist—worked on the Manhattan Project at Los Alamos. He was only twenty-six years old. Accidentally irradiated himself while performing a critical mass experiment on two half-spheres of plutonium. Took him a month to die. While his body was slowly shutting down from radiation poisoning, you know what he did with his last thirty days, hmm? He worked. He tried until his last breath to understand what had happened to him so that others could learn from the tragedy, so that his work, his death, wouldn't be rendered meaningless.— McKay
Exploring the dead world of the Dorandans, the team finds the débris from a destroyed Wraith fleet in orbit. On the planet's surface, the team discovers a surprisingly intact Ancient outpost. Investigating the outpost, the team find that it houses a superweapon that is responsible for the destruction of the aforementioned Wraith fleet. McKay and Zelenka get the lights on and are delighted to discover that the outpost was in the process of developing an energy source that would make ZPMs obsolete. They used it to destroy the Wraith, but sadly all died somehow before it could be perfected.
Meanwhile, Teyla takes Ronon along on a trading mission to the planet Belkan. Ronon is no better at negotiating than Sheppard is, but they discover quite by accident that there are other Satedan survivors scattered across the galaxy—Ronon is not actually the Last of His Kind. Ronon is understandably overjoyed to learn that 300 of his people have survived, and immediately starts looking for his former commanding officer, a man named Kell. Using Teyla's contacts and general negotiating skills, they are able to get an audience to see him, and Ronon unceremoniously shoots him in the face. He later explains to an enraged Teyla that during the invasion Kell deliberately sacrificed Satedan lives in order to ensure his own escape, and the man had it coming. Teyla reluctantly agrees, but warns him that the rest of the Atlantis expedition will not.
The work at the Ancient outpost initially seems to be coming along very well, although not everybody is as confident as McKay that he will be able to solve a problem the Ancients couldn't. The first real test, however, suffers an unexpected overload, almost preventing McKay from shutting it down and killing one of the scientists. The death shocks everyone, particularly McKay, and they evacuate back to Atlantis to figure out what went wrong. McKay becomes more and more obsessed with getting the project to work, and begs Sheppard to take him back to the outpost. Weir and Caldwell eventually give permission for continued testing, persuaded by Sheppard and McKay's enthusiasm and by the vast rewards if the project is successful.
While McKay is setting up for the test, Zelenka calls in. He has just finished analyzing the data from the first test and discovered that the project cannot in principle succeed. Because the Laws Of Physics break down and create unpredictable exotic particles that are impossible to block, and turn into deadly radiation once outside the chamber.
Thus, the device will always overload unpredictably at any power level. This is what killed the planet after the Wraith had been defeated—the Ancients operating it had only been able to shut it down at the cost of their own lives. McKay brushes him off, insisting that he has solved the problem, and proceeds with the test.
The gun successfully targets and destroys the Wraith debris in orbit—and then begins to overload as Zelenka predicted. McKay continues to work, convinced he can correct the problem, until Sheppard manages to finally talk him down. By that point, however, it's been going too long and nothing can prevent catastrophic overload—which is to say, the whole planet going up.
Sheppard and McKay flee in the jumper, but the gun is still targeting debris around the planet, preventing them from reaching the gate. They are rescued at the last moment by Caldwell and the Daedalus, which then retreats into hyperspace as the planet explodes, taking five-sixths of the solar system with it.
Tropes:
- Apocalypse How: Initially somewhere between a class 3A and a class 5; McKay manages to upgrade it to a class X-2.
- Badass Longcoat: Ronon and Teyla wear them on their trading mission.
- Big Damn Heroes: Col. Caldwell and the Daedalus show up just in time to shield Sheppard and McKay's puddle jumper from the space gun while they escape the system via Stargate.
- Blunt Metaphors Trauma:McKay: It's a cakewalk!
Zalenka: I don't think it matters how much cake you walk on. - Break the Haughty: Rodney's arrogance is on full display, he believes that he alone can perfect the Ancient reactor technology when even its own designers couldn't make it work. It's only when the experiment is about to blow up in his face (literally) that the realizes how wrong he was.
- Declaration of Protection: Despite pressure from the SGC and the Pentagon, Elizabeth is unwilling to let Rodney make a second attempt to power the weapon, even when he’s convinced himself he’s perfected the science behind it. This trope is revealed to be the reason in her conversation with Sheppard and Caldwell.Weir: I’m trying to tell you I know Rodney McKay and there are times when I have to protect him from himself.
- Earth-Shattering Kaboom: that takes out three quarters of the solar system. Possibly even five sixths. It's not an exact science.
- Everyone Has Standards: Even with his ego, Rodney's unwilling to scapegoat the late Collins for the failure of the first test. If anything, he's equally disgusted that Caldwell suggested it was human error (though to be fair to Caldwell, he was merely trying to find a rationale to allow Rodney to continue the research rather than maliciously using Collins as a scapegoat).
- Foreshadowing: In a moment of
Fridge Brilliance demonstrating McKay's overconfidence, he says Daghlian's age wrong; he tells Sheppard he was 26, but in real life
he was 24. - Get A Hold Of Yourself Man: While no slapping takes place, Sheppard manages to bring Rodney to his senses by telling him about pilots who have tried to fix their failing planes when the safer choice would be to bail out, right up until they hit the ground.
- Going Critical: The reactor tends to overload at the slightest provocation, frying some poor tech the first time and taking out the entire solar system the second time.
- Hoist by His Own Petard: The Dorandans were wiped out by their own out-of-control space defense cannon.
- Hope Spot: After Collins' death, it looks like Rodney's finally realizing Sheppard was right and that the technology is too dangerous and he can't succeed where the Ancients failed. Then his ego comes roaring back with a vengeance.
- Hyperspeed Escape: The Daedalus.Sheppard: Recommend you jump to hyperspace. It's gonna be a big bang.
- It Won't Turn Off: The Arcturus reactor and the linked weapon. They barely manage to get it under control the first time, but McKay can't stop it from overloading the second time.
- Jerkass Has a Point:Dr. Weir: Why are we mincing words, Colonel? You want the weapon.
Col. Caldwell: Yes. I do. A weapon that could effectively eliminate the Wraith threat is very attractive to me, and to the people that I work for. I'm not hiding that fact. But there's more to it, isn't there? No more hunting for ZPMs. The shield at full strength. Faster, more powerful ships. How about a power source that can provide the energy needs for an entire planet? No more fossil fuels...
Dr. Weir: Okay, I get it. And if it worked as advertised, it would be wonderful. - Not Helping Your Case: During Weir's shouting match with Rodney in the penultimate scene, she exclaims that he blew up 3/4 of a solar system. Rodney corrects her, saying it's really more 5/6 of said system...which only pisses off Weir even more, as it shows Rodney's still listening to his ego rather than to her.
- Outrun the Fireball: Averted. McKay states outright that it would be impossible.
- Readings Are Off the Scale: Something similar is said by one of the scientists the first time they try to test the reactor.
- Reality Is Out to Lunch: This is what caused the Ancient project to fail. It doesn't matter how much power you try to draw, the very attempt to harness vacuum energy from our own universe causes reality to break down within the containment chamber. This inevitably creates exotic particles that are impossible to block, and they turn into hard radiation once they breach through. The Ancients managed to stop the device, but sacrificed their lives and the lives of everyone on the planet to do so. Rodney isn't as smart, and he cannot stop the reaction going critical.
- Rewarded as a Traitor Deserves: Ronon kills Kell for sacrificing Satedan soldiers to save himself during the Wraith attack. Tellingly, none of his men make any effort to save him, or even avenge him after the fact.
- Remember When You Blew Up a Sun?: The destruction of Doranda becomes this for Rodney for the remainder of the spinoff's run — and unlike Samantha Carter over on SG-1, it's not a Moment of Awesome for Rodney. It becomes his most shameful, humiliating moment as a member of the Expedition (and, depending upon the circumstances, either gets brought up for black comedy or if Rodney's getting too haughty again).
- Shout-Out: Both the episode title and much of McKay's dialog invoke parallels between the research at the Ancient outpost and the Manhattan Project.
- Suicidal Overconfidence: Rodney invokes this, as he's utterly convinced that he can make the power source safe to use, even when the power source is about to blow up the planet he and Sheppard are currently on. Sheppard manages to get through to him by telling him about pilots he's known that have had something go wrong in their planes and refusing to bail out trying to fix it, right up until they hit the ground.
- Values Dissonance: Invoked. Teyla warns Ronon not to tell the Atlantis mission about Kell's murder, basically for this reason.
- Wave-Motion Gun: The Ancient defense cannon.
