We open with Earth-203 and the Birds of Prey, for just long enough to see them get wiped out and join the ranks of the disappeared Earths.
Ray’s Paragon detector shows the group the three remaining Paragons; Barry Allen the Paragon of Love, J’onn J’onzz the Paragon of Honour, and Ryan Choi the Paragon of Humanity. Ray, Iris, and Ralph head over to Earth-1 to fetch Ryan, while Diggle bitches the Monitor out for both Oliver and Lyla.
Kate’s holding tight to her kryptonite in every interaction with Kara this episode, while Kara is holding on even tighter to the idea of restoring Earth-38 using the Book of Destiny despite everybody, Lex Luthor included, pointing out what a terrible idea this is.
Cisco gets his powers back thanks to the Monitor, we get a bit more backstory on how Nash became Pariah, and, much more importantly, we visit Earth-666 and are introduced to Satan himself: Lucifer Morningstar! He owes Constantine a favour, so after trying his luck with both Mia and Diggle, he gives them a card that will allow them to visit purgatory and bring Oliver’s soul back with them. Lucifer also deliberately mispronounces Constantine just to mess with him. Back to Lian Yu we go!
In the Anti-Monitor’s hideout, which it turns out is the place that Nash was trying to break into during this season of The Flash, we find Earth-90 Flash, missing since Elseworlds, running on the Cosmic Treadmill of all things! He’s powering the antimatter cannon. Oh and nobody, NOBODY told Caitlin, Cisco, or Barry that Earth-2 was gone, and they, the group of heroes with the most ‘multiversal awareness’ as it were, didn’t notice. So we get a quick “oh no, Harry and Jessie” and move on. Cisco frees Earth-90 Barry, but is told to put him back, because the treadmill is booby-trapped. Earth-1 Barry naturally refuses.
Meanwhile, Ryan Choi has exactly zero interest in becoming a hero.
Lois sees that Earth-73 is gone, leaving only seven more Earths. Kingdom Come Superman isn’t taking this well, but gives his hope speech from the trailer and hops back to work. Black Lightning walks out from a corridor (having been dropped off by Pariah from maybe Earth-73) and starts chucking lightning about like that stuff’s free. Jefferson Pierce has lost his Earth too, but Barry convinces him to blast the Antimatter cannon to slow its progression again.
Kate manages to talk down Kara, and surprisingly doesn’t use the kryptonite when things get hairy. Meanwhile Barry and Barry Flash-time-speed-round and Diggle convinces Oliver back round to having a soul with a bro speech. In a second round of speeches making the world go round, Iris convinces Ryan Choi, the Paragon of Humanity, to be the human among the supers, grounding them– which isn’t how she put it, but screw it, this was better. We then get the news that we’re down to the last Earth. Which, honestly, was a little anti-climatic when you consider how many other Earths we’ve seen go, and the last six just got off-screened. If anything you’d think they’d get the focus.
Getting reading to disappear in Crisis as he’s still convinced he’s meant to, Barry says a genuinely heartfelt goodbye to Caitlin and Cisco, and it’s a solid moment that would only have been better if Joe was also there. Then Earth-90 Barry jumps in and steals his speed, stating that the Monitor never said which Flash had to die, and despite Barry’s protests, Cisco takes the initiative and helps Earth-90’s Flash make his sacrifice play for the good of the multiverse. He tells our Barry to keep riding the lightning, gets a lovely flashback to the early 90s, and disintegrates by running the wrong way on a treadmill. Yeah it sounds goofy, and yeah it was predictable the moment we saw the Earth-90 Barry was back, but damn if it wasn’t a good scene anyway. The antimatter wave is stopped. Earth-1 is saved.
As they’re leaving Purgatory, Oliver’s soul buddy team are stopped by Jim Corrigan / The Spectre (but not the Earth-1 Corrigan, as noted by Constantine) who gives a speech parodying the opening spiel from Arrow, and then stating he’s there to pass his powers on to Oliver, who says goodbye to Diggle and Mia and sends them and Constantine back to the Waverider before disappearing off into the multiverse with new glowy eyes.
Barry and Jefferson bond of their dead dads, and Kate tries to give Kara the kryptonite she’s been palming, but in a massive heel-face-turn that flies in the face of multiple seasons of really stupid kryptonite-based character development she refuses and tells her to keep it.
The whole team is together, with Harbinger arriving and pretending to have been lost for the entire episode– it turns out she’s a host for the Anti-Monitor and she knocks out Diggle, kicks the crap out of Kingdom Come Superman with ease before downing all of them. The Monitor claims that Pariah can still win it for them. The Monitor is beaten in a Dragonball Z beam struggle with Harbinger/Anti-Monitor and his essence is absorbed, and Earth-1 is destroyed by the restored antimatter wave leaving only the Waverider. Pariah sends the seven paragons away somewhere they can’t be touched, specifically the Vanishing Point from Legends season 1, as the Waverider is atomised.
The Paragons are the only people left in the multiverse, and things look pretty dire. And THEN Kingdom Come Superman appears to die, but gets swapped out for Lex Luthor because he tinkered with the Book of Destiny page he’s been holding onto. The brilliant, evil motherfucker.
EDIT: I never did finish this series of posts. The fourth part was good, set up a bunch of stuff, and then erased the meaning behind all of it in the epilogue by re-revealing the multiverse. Sure, it sets up for the rest of DC’s properties and the mainstream multiverse concept for the regular audience, but it kind of invalidated the whole arc.