SPOILER ALERT: Do not read if you have not yet watched “Crisis on Infinite Earths: Part Three,” “The Flash” episode of the 2019 “Arrowverse” crossover.

Tuesday night was the official midpoint of the ambitious “Crisis on Infinite Earths” crossovers, with an episode of “The Flash” that also marked the final episode of the year for the DC series. As such, it was as full of Easter eggs, plot twists, and a whole lot of… well, crisis.

But first a special cameo, this time by Ashley Scott as “Birds of Prey’s” Huntress. She barely had time to appear on-screen before New Gotham and the rest of Earth-203 blew to smithereens, marking another Earth obliterated by Anti-Monitor and the anti-matter smashing through the universe at record speed. With that the plot returned to Earth-1, where the gang reconvened in Central City to work on the Paradigm-finder and receive news that Kara aka Supergirl’s (Melissa Benoist) other loved ones on Earth-38 had made it out alive.

Joining the action (finally) was also Diggle (David Ramsay), who learned about Oliver aka Green Arrow (Stephen Amell) and his new half-dead status along with the unpleasant fact that his wife, Lyla aka Harbinger (Marie Anderson) was probably hanging out with Anti-Monitor. He joined Constantine (Matt Ryan) and Mia (Katherine McNamara) in a bid to find Oliver’s soul in purgatory, with a little help from Lucifer (Tom Ellis) on Earth-666.

Back in Central City, Ray aka The Atom’s (Brandon Routh) machine finally came through, revealing the three final Paragons — including Ryan Choi (Osric Chau). As Ray, Iris (Candice Patton) and Ralph (Hartley Sawyer) went off in search of Ryan, Barry aka The Flash (Grant Gustin), Cisco aka the newly resurrected Vibe (Carlos Valdes) and Caitlin aka Killer Frost (Danielle Panabaker) worked on opening the door to the source of the anti-matter sweeping the universe.

They found it with the help of Pariah (Tom Cavanagh), only to reveal the machine generating the power was being powered up by Earth-90’s Flash (John Wesley Shipp). Barry and co. pulled him off the treadmill and activated Anti-Monitor’s failsafe in the process, leaving them with precious minutes to figure out a plan or risk blowing up all of the remaining worlds at once.

Pariah came through first by recruiting Jefferson Pierce aka Black Lightning (Cress Williams), who managed to use his own currents to hold off the machine while the Flashes figured out a way to reverse engineer the anti-matter machine. It turned out they needed to essentially run backwards on the treadmill as quickly as possible, but when Barry volunteered for the task Earth-90’s Flash temporarily stole his powers instead and hopped on. As he ran out the matter the show inserted a flashback to the 1990 series “The Flash,” (yet another Easter egg) and with that, Earth-90 Flash was toast, too. His sacrifice ended the anti-matter in the nick of time; Earth-1, a.k.a. the last Earth standing was about to be blown up too.

Meanwhile in Purgatory, Mia and Diggle found Oliver and managed to give him his memories back, but just as he was about to return to his former body, Jim Corrigan (Stephen Lobo) appeared, informing Oliver that he was destined for a higher calling — saving the multiverse. So he stayed behind and sent his loved ones packing, rendering the whole mission pointless.

Back on the ship, Kara and Kate aka Batwoman (Ruby Rose) spent most of the episode arguing over whether to open The Book of Destiny, but also bonding over hope and courage — until the anti-matter stopped, everyone was united, and Harbinger finally resurfaced. Except it wasn’t really Harbinger but Anti-Monitor in disguise. With the sweep of a hand he blew up Earth-1 and incapacitated the superheroes so that he could finish off The Monitor once and for all. That left Pariah to become the hero he was meant to be, and with just seconds left before the ship blew up, he sent the Paragons to The Vanishing Point so they could reconvene and hopefully stop Anti-Monitor once and for all.

Then, in one final twist Superman (Brandon Routh) inexplicably fell and succumbed to red lasers, only to be replaced by one Lex Luthor (Jon Cryer). The baddie had actually rewritten destiny — he put his own name as one of the seven Paragons, wiping out his enemy and saving himself in the process.

And with that, “Crisis on Infinite Earths” wrapped until the new year.

“Crisis on Infinite Earths” wraps on Jan. 14 with back-to-back episodes of “Arrow” and “DC’s Legends of Tomorrow.”

UPDATED: This report has been updsted to refect that Stephen Lobo played Jim Corrigan in the episode.