Supergirl wakes in her apartment to find her sister Alex waiting for her but Alex has no recollection of anything strange happening. Supergirl receives a call from Dream Girl telling her she’s late for the Nobel Peace Prize ceremony. She arrives in seconds and tries to tell Dreamer of what’s going on but is stunned when Lex Luthor is announced as the winner of the Nobel Peace Prize.
At the DEO, Supergirl cannot understand why Lex is seen by the world as a good guy (and one of Supergirl’s biggest supporters) and is then surprised to discover the DEO is a Luthorcorp subsidiary, making Lex her boss. Martian Manhunter arrives and tells Supergirl that he remembers everything as well, and that this new world is the result of the restart of the universe.
Answering a distress call, Supergirl confronts Weather Witch but is joined by the Flash and both think the other is on their Earth. A member of the public, Marv, asks them to autograph a photo of them, and explains that the two heroes have teamed up on a regular basis, usually with Green Arrow and a Legend or two.
In Central City, maintenance workers find an unconscious Nash Wells beneath the city.
White Canary walks in Star City and finds the Atom in the bar they attended for the quiz night, but Ray has no memory of Crisis. Martian Manhunter arrives and explains that the seven Paragons are the only ones who remember the pre-Crisis universe. He gives a telepathic mind-dump to the Atom, allowing him to remember everything, and says he’s been doing the same to their friends, but that there is no sign of Green Arrow.
In Team Arrow’s headquarters, she finds Diggle and the team who have already had their memories restored by Martian Manhunter. White Canary thinks there’s a chance Green Arrow can be found but the Team know that he’s gone.
Back in Central City, Nash has been taken to Star Labs, and Martian Manhunter restores Frost’s memories, now remembering that Nash is responsible for releasing the Anti-Monitor. Nash reawakens and, one brain dump later, apologises for all he did as himself and Pariah.
Supergirl and Flash meet the others at Team Arrow’s HQ and are told that Green Arrow didn’t make it. An attack alarm is sounded as a giant Beebo toy strolls down Central City’s roads. White Canary contacts her team and is told by Ava that Heat Wave is already in town at a signing for his romance novel.
Supergirl, Flash, Heat Wave, and the Atom attack Beebo and are joined by Batwoman and they realise that it was nothing more than a distraction. Sargon the Sorcerer animated the toy while he robbed a bank; once he was taken out, Beebo is destroyed.
Nash arrives and tells them that he is detecting anti-matter which means things haven’t finished. Elsewhere, White Canary and Flash discuss having lost Green Arrow, and what he gave to the world with his sacrifice. They are suddenly attacked by a shadow demon and realise, with Martian Manhunter’s help, that the Paragons are being hunted. They quickly rescue Ryan Choi from a demon and reconvene at Arrow HQ.
Nash reveals the Anti-Monitor is still alive; the Atom and Ryan Choi come up with an idea to alter the Anti-Monitor’s energy so that he shrinks forever.
As the shadow demons attack Star City, most of the heroes arrive to defend the city, but the demons ignore them and combine to form the Anti-Monitor at the docklands called Perez Landing. Other shadows attack Star Labs and are joined by Black Lightning.
The heroes attack the Anti-Monitor, but their attacks are repelled by a force field time and again. He enlarges himself and is taken on by the flying heroes, while the other heroes defend themselves against more demons. The shrink bomb is finished and delivered by the Atom to Supergirl who hurls it at the Anti-Monitor who shrinks to nothing instantly, ending the shadow demons as well.
At the end of the day, a Presidential address informs the country that Green Arrow sacrificed his life.
We see once more the creation of the universe, as we did at the start of the series, and the creation of a new multiverse:
Earth-2 featuring the characters from Stargirl and the new Justice Society.
Earth-12 featuring the Corps from the Green Lantern film.
Earth-19 featuring the lead character from the Swamp Thing series.
Earth-9 featuring characters from the Titans show.
Earth-21 featuring characters from the Doom Patrol series.
Earth-96 featuring Superman from Superman Returns but one who, judging by his costume, hasn’t faced the tragedy of losing his wife and friends to the “reject from Gotham.”
The combined Earth, now called Earth-Prime, sees seven of the heroes offering tributes to Green Arrow. Once finished, the Flash reveals they’re in a disused Star Labs facility where, if needed, they could reconvene. He reveals a table with chairs for each of them, including Green Arrow.
 – This is Marv Wolfman, writer of the original CRISIS ON INFINITE EARTHS comic book series.
 – Beebo, though a stuffed children’s toy, has oddly been an antagonist of the Legends of Tomorrow on more than one occasion.
 – Named for George Perez, the main artist on the original CRISIS ON INFINITE EARTHS comic book series.
 – Earth-2 is home to the Stargirl TV series. As the series hosts the Justice Society of America, this numbering makes sense as that was the Earth the JSA fought on in the original pre-CRISIS comics.
 – Earth-12 is now home to Green Lantern and the Guardians of the Universe with clips from the 2011 film.
 – Earth-19 is named for 2019, the year the short-lived Swamp Thing series was aired.
 – Earth-9 gives no clue to the numbering of this Earth.
 – Earth-21, like the above, gives no clue.
 – Earth-96 shows that Superman-96, whom Lex Luthor replaced at the end of Episode 3, has been reborn.