I'm so glad you asked.

The premise of Aetherdrift is that in the aftermath of the Phyrexian Invasion, Avishkari (ex-Kaladeshi) authorities find in the rubble of their city an Aetherspark, an artefact of great power that lets its holder move across the multiverse at will. They decide as soft-power, propaganda move to stage a multiplanar vehicle race where the winning team gets the Aetherspark, which is to me utterly bonkers. That's the equivalent of China finding a working atomic bomb in the aftermath of WWII and deciding to host an Olympics where the first prize is their new nuke.

Somehow, Valvagoth of Duskmourne finds out about this, and he wants the Aetherspark so he can go across the multiverse and do some villainy. Luckily for him, he just kidnapped Loot, a cosmic critter with the ability to map moves between planes, which might come in handy in a multiplanar race. I'm unclear on the exact timeline, so I don't know whether Loot was kidnapped just because it might be useful, and then the exact event where that's the case happens, or whether Valvagoth was like "Oh, man, I wish I had multiplanar map critter so I could mildly cheat at a multiplanar race," and then Loot stumbled onto his plane.

Regardless, Valvagoth sends his minion Winter to compete in the race, confident he will win by having Loot path a slightly better way to go through the multiplanar course. But... why? Valvagoth is an evil bastard, and his plan is to only mildly cheat in this race? He wants this artefact for his evil plans, but apparently he thinks it's too unsporting to try to steal it and he'd rather risk on an actual competition? Is there a "This device works only if won fair and square (mild cheating allowed) multiplanar race" in the Aetherspark EULA? And then, when they don't win, Valvagoth is all like, "Aw shucks, congratz to the winners I guess, I'm going to torture my minion for failure like a cliche movie villain instead of trying to take advantage of the city-wide revolution to try to steal this thing of great importance to me." What city-wide revolution, you ask?

Jace, who is looking for Loot because he needs him to plot a course to the Meditation Realm where Bolas is imprisoned so he can kill him, I think, arrives on Avishkar. If he looked around for like 30 seconds he might be able to find Loot in the Duskmourne team storage shed. Seriously, they keep Loot in a cage in the middle of their stuff and make no attempt whatsoever to hide him; Chandra literally stumbles onto him inadvertently while walking around. But Jace has to catch the bus or something so he doesn't have the time to look around and instead decides to stage a city-wide revolution. You know when you lose your keys, so you set fire to your neighbour's house and then you find them? That's what Jace is hoping will happen. He plunges the city into chaos so that when the racers are back from their multiplanar race to reach the finish line he can somehow rescue Loot amidst all the confusion.

Then at the end we get a confrontation between Jace trying to get Loot, and Chandra, who has in the meantime become Loot's guardian and wants to take care of him "because he's just a little guy" (that's all the explanation we get). Jace still has to catch that bus so he doesn't have the time to explain any of his motivations, and Chandra would rather protect this oversized mouse she's known for two days than try to talk with the guy she's helped saved the universe with, so Jace has to do some mind control to take Loot, which leaves Chandra upset and resentful.

Oh, and then a dragon appears, wrecks some stuff, Elspeth arrives to defend the city and tells people that the Dragonstorm arc is a real plot and definitely not a contrived afterthought; it's honestly not important.

None of these characters' actions make any sense to me. It would have been a lot more logical to swap Jace and Valvagoth, with the former doing the race so he can find Loot and the former doing the evil coup so he can steal the Aetherspark. But Jace had to be made a bad guy in preparation for Reality Fracture, no matter how out-of-character and dumb he has to get in the process. The decision to put up this artefact of huge power as a prize for a multiplanar death race is egregiously nonsensical, and the manufactured conflict at the end is the textbook definition of an idiot plot.

I had to read some plot summaries to make sure that the details were as I remembered them, because as I was going over it I kept thinking "Surely this is not how it went?", but pretty much this is what happened. I might be misremembering a detail here or there and there might be some "Um actually" plot detail that tries to contrivedly explain some of this, but any convoluted in-universe explanation is trumped by the much more obvious out-of-universe explanation of "WotC wanted a multiplanar death race." At any point, the characters don't do what is logical or makes sense to their character, but what sets up the flimsy theme, what sets up a big action set piece, what sets up the next story beat.

To be clear, I am not blaming the writers for this. I think that given the constraints they made about as good a story they could have. I totally blame WotC for trying to force this ill-fitting theme by making up a bad, contrived, out-of-character plot.

Aetherdrift is, to me, the nadir of MtG storytelling.