McKay: You know we could be a team. You could be my sidekick.
McKay: Yeah, it'll be like Batman and Ronon. Has a nice ring to it.
While wandering around the city turning off unnecessary systems, McKay and Zelenka discover a previously unkown Ancient lab. When McKay tries to figure it out, he gets zapped by a strange energy beam. Dr. Beckett gives him a clean bill of health, but it's not long before he starts to exhibit Special Powers! At first it's just enhanced hearing and the occasional telekenesis, but soon he's reconfiguring the city power grid and inventing new forms of math.
It turns out that the machine that zapped him reconfigured his DNA; its purpose was to physically prepare people for Ascension. While McKay enjoys the perks of being an all-but-ascended superhuman (which now include mind reading and more-than-usual insufferable genius), Zelenka sets himself to figuring out the machine that did it - and he and Weir discover the catch. McKay is going to keep evolving until he reaches the point of Ascension - at which point all of his lower functions will shut down, and he will either Ascend or die. And since this is McKay we're talking about, and Ascension has spiritual as well as a physical component, it pretty much looks like option 2 here. After his standard "I'm about to die" freakout fest (rendered a bit shorter than usual by his ability to read minds) McKay decides to dedicate his last days to improving Science as much as possible.
The others encourage him to at least try to Ascend - and Weir points out that he can always retake human form afterwards. McKay builds himself an Ascend-O-Meter to keep track of how well he's doing, and Sheppard, as the local expert on Ascension, does his best to pass on the tips he learned during his six months with the Ascension colony.
McKay embarks on a campaign of good deeds and soul-searching; he writes Weir a glowing biography, heals Ronon's scars, serves Teyla some tea, and apologizes to Zelenka for being such a Jerk Ass
all the time. While the Ascend-O-Meter shows some improvement, however, it simply isn't enough. McKay despairs of being able to Ascend and starts leaving instructions for the disposal of his remains. And then he collapses.
The med team rushes McKay to the infirmary, where Beckett confirms that it's pretty much over. As he nears Ascension, his body is losing its ability to do more basic things, like breathe and keep his heart going. The team gathers around for a somewhat emotional farewell as the Ascend-O-Meter ticks down. Just as everything hits zero, McKay suddenly grabs Beckett and whispers something - a way to save himself! They rush him back to the machine that caused the trouble in the first place, and Beckett and Zelenka (who's been working down there this whole time) are able to use it to reset McKay's DNA, based on an old blood sample. Everything is zapped back to normal, and all our heroes have to worry about now is all the awkward things they said to one another over the course of the episode.
- A Mind Is a Terrible Thing to Read: It takes McKay from the Infirmary to the Gate Room, to go from thinking that mind reading is cool to becoming very annoyed by it. He's particularly disappointed to realise that the woman walking passed was thinking Ronon was hot, not him.
- Ascend to a Higher Plane of Existence: One of McKay's two options. The other is death.
- Bottle Episode
- Dying Declaration of Love: Inverted - and open to interpretation. McKay chooses to interpret it as literally as possible.
Weir: Rodney, you're a good person. Know that we love you.
McKay: You love me? Really? All of you?
- And later
McKay: I may not be able to understand this new math I created, but I distinctly remember that you said you love me.
Weir: Actually I said we love you and...
McKay: And what? You were just saying that because you thought I was dying?
- Flowers for Algernon Syndrome: McKay is especially frustrated by no longer being able to understand the new math he invented.
- Healing Hands: One of McKay's superpowers
- Hilariously Abusive Childhood: Zelenka, to hear him tell it.
- Man Hug: McKay and Ronon. Twice.
- Mind Reading: One of McKay's superpowers
- OOC Is Serious Business: You can tell how seriously McKay is taking his impending doom, because for the rest of the episode he is calm, humble, and considerate of others.
- Pet the Dog: Rodney deciding to use some of his remaining time to perform good deeds for his friends. Particularly apologising to Zelenka for how badly he's treated him over the years, as well as healing the scars on Ronon's back.
- Scars Are Forever: Subverted by Healing Hands.
- Superpowers For A Day
- Technopath: One of McKay's superpowers
- With Great Power Comes Great Insanity: Discussed (but otherwise averted)
McKay: (to Ronon) She wants you to shoot me if you think for even one second that I might be trying to take over the city for my own evil purposes.
- The X of Y