The animated film Superman: Man of Tomorrow was released in 2020 and became the first in a series of connected animated films with a shared universe and characters, dubbed the Tomorrowverse. In 2024, the Tomorrowverse would face it’s biggest threat, the Crisis on Infinite Earths, with the event taking place over three films.
Rather than being told in a linear fashion, Part One follows the Flash as he is propelled through different moments in his life, bouncing back and forth as the Crisis looms.
At the start, we see the Flash running through a multitude of Earths being destroyed before he returns to the lab just after the accident that gave him superspeed. We cut to the diner where he meets Iris for the first time before being interrupted by a homeless man who tells him to get up.
The scene shifts to Flash, dazed and confused, during a fight with Amazo, before he’s rescued by Superman. Flash remembers the battle but it goes poorly for Superman and Green Arrow as the android drains their powers. In need of help, and at Superman’s request, they head to Wayne Manor and Bruce Wayne reveals he’s Batman and helps them.
Flash moves through time again and is walking, as Barry, with Iris just before their wedding when, at Iris’s prompting, he tries to give a homeless man – the same man from the diner – some money. The man warns him that all worlds are ending, grabs Barry’s head and thrusts him back into the time line.
Back at the Batcave, Superman is being treated and Batman, Green Arrow, and Flash talk about defeating Amazo, and discuss Professor Ivo, Amazo’s creator, and how he works for Lex Corp. Batman suspects the original attack by Amazo was a distraction for something else. The next morning sees Superman mostly recovered, before forming a superteam is discussed with membership to include Vixen, Martian Manhunter, and Green Lantern (who turns them down.) Once more, the homeless man approaches Flash and tells him he must bear witness.
Flash appears in a Central City where the civilians are terrified of him and realises he’s on a different Earth where he finds a speedster robbing a bank. Johnny Quick tells him about the Crime Syndicate who arrive and capture him before he’s thrust back through time.
He appears at the announcement of the Justice League’s formation which is attacked by Amazo. The League set about saving the gathered reporters with Flash moving at superspeed when he realises Amazo is alerting him to threats to the League’s safety because his primary motive is to prolong and improve human life. When Flash challenges him about Amazo’s recklessness, Amazo reveals he has a “new best friend” – Lex Luthor, who arrives wearing a giant battlesuit. Luthor tells Amazo to prioritise draining Superman but the League rescue him, and Batman decides to call in an automated airstrike to deal with both Amazo and Luthor, despite the League’s reservation. Realising Amazo is confused due to conflicting mission parameters, Flash enters the time line, this time deliberately.
He briefly appears on the Monitor’s satellite and is stunned by the view of multiple Earths, before disappearing again.
He finds himself back on Earth-3 in the Hall of Crime, being questioned by the Crime Syndicate. Flash tells them he’s from another Earth and Superwoman tortures him to learn he’s telling the truth, and Ultraman realises he now has a new Earth to conquer. As the Syndicate try to get Flash to direct them to his Earth, the homeless man appears casting a spell that incapacitates the Syndicate and shows them the future destruction of Earth-3, sending Flash back through the time line.
He wakes on his wedding day and needs to see Iris despite it being bad luck. He tells Iris that he’s been bouncing through time and that something major is going to happen on their wedding day.
He runs back into the time line and now appears in Lex Corp where Professor Ivo, the creator of Amazo, is being held captive. Ivo tells Flash about the hyper-aging disease that is killing him and the research Lex Luthor had him undertake in order to extend life, including access to an alien life form that is added to Amazo that would allow for the absorbtion of metahuman’s powers. Ivo’s programming was for Amazo to help people – it was Luthor’s reprogramming that has turned the android bad. As they speed back to the League’s formation, Flash bounces through time once more.
Back on Earth-3, the homeless man shows Flash the destruction happening outside the Hall of Crime, as volcanos and lightning storms wreak havoc. The Syndicate attempt to stop buildings crashing, but only when the threaten the Hall. The homeless man claims to be being punished to witness all Earths’ destruction and while he doesn’t remember what he’s being punished for, he says that Flash shares his guilt.
We head back to the battle at the League where Amazo, directed by Luthor, is attacking the League despite his misgiving. Batman’s airstrike arrives but is struck down by Luthor’s battlesuit before he commands Amazo to drain all of the League. Flash arrives with Professor Ivo who convinces Amazo that Luthor is lying to him and that life cannot be extended. Ivo asks Amazo to release the gathered energy into him but the act kills Ivo. Amazo, with help from Batman, realises that Ivo was infected with the hyper-aging disease by Luthor in order to motivate him to create Amazo, all so Luthor could eventually steal the absorbed powers. Amazo easily destroys Luthor’s battlesuit and appears to be ready to kill him, but Flash convinces him to stop, and Amazo returns the League’s powers to them before powering down as he realises he has been the villain. With Batman realising there is strength in differing opinions, the assembled heroes agree to form the Justice League.
We jump to a much older Barry and Iris, in a world that appears frozen, with birds simply hanging in mid-air. The scene shifts quickly, however, back to their wedding day as Barry tells Iris that something big is going to happen. Barry reassures her that they will grow old together before they head to their wedding where Vixen is officiating. As the ceremony begins, a floating female with flaming hair appears in the room – Harbinger – who has come to recruit the Flash and the other heroes.
Harbinger transports them and heroes from other worlds to the Monitor’s satellite. Among the heroes Harbinger brings is Dr Hoshi whom Harbinger takes to a machine that creates the costume for Dr Light, and then triggers her powers. Having seen what happens with that machine, the other sole civilian aboard also uses it and becomes Psycho Pirate. Harbinger reveals to Dawnstar of the Legion that she is actually Kara, Supergirl from Dawnstar’s era.
The heroes are interrupted by a Monitor who explains his vow to watch but not interfere, and how he has broken that vow to alert the heroes to the threat that is approaching. He shows them an anti-matter wave that is approaching all realities, and hopes that they can stop the disaster together.
We return to the older Barry and Iris who are heading out to complete a project they’ve been working on.
Back at Earth-3’s destruction, Power Ring gathers the Syndicate as the anti-matter wave tears through their world. Ultraman and the others launch themselves at the wave in hopes of defeating it, despite the Flash’s protests and the wave destroys each of the Syndicate in turn.
On the Monitor’s satellite, the Question doubts the Monitor’s motives, with Batman questioning why Earth appears to be the focal point. The Monitor claims that in each universe, Earth is attacked first and, if it falls, the rest of that universe is doomed. The Psycho Pirate asks why the heroes don’t band together, take over the satellite and use it get back home, before the Flash has Wonder Woman use her lasso of truth on him so he can tell them of his time on Earth-3 and it’s destruction. As he speaks, Superman of Earth-2 uses his vision to see another Earth destroyed. Batman deduces the heroes have been assembled as a think tank and the Monitor agrees that the genius heroes are here to devise a solution while the others are there to build whatever they come up with.
The elderly Barry heads to his cellar where Amazo’s disembodied head waits for him and delivers detailed instructions for Barry and Iris to complete their project.
On the satellite, the scientists struggle to find a solution until Flash mentions that he can vibrate between dimensions and explains that Earth-3’s speed force has supercharged him which may be why he is experiencing time in a non-linear fashion. This allows the scientists to come up with plans for giant tuning fork towers that would vibrate at a frequency allowing the anti-matter wave to pass through the Earths, and construction begins across multiple Earths.
Old Barry continues working in the frozen time world and it’s revealed he’s finishing one of the towers while an anti-matter wave hovers in the distance.
The other heroes creating towers are stunned to watch the wave speed up and target their Earths as though it were sentient and understood what they were doing. On his Earth, Barry is confronted by the homeless man once more and told to run to Iris. As the wave approaches, Flash refuses to lose Iris and begins vibrating. They vibrate so fast that time appears to stop for them, giving them time to grow old together as they work on the completing the tower. The elderly Barry and Iris work on their tower before Iris collapses and, after they say a tearful goodbye, she passes away. Barry, with Amazo plugged into the tower, prepares to slow down to drop out of the frozen world so that he can charge Amazo and the tower with his speed.
Flash’s tower powers up and kickstarts others on other Earths and the anti-matter wave passes through the Earths leaving them unharmed.
The Monitor is surprised at the success of the plan and admits as much to the Spectre.
The elderly Flash recovers but finds Amazo has been destroyed. The Spectre appears to Flash and tells him that the guilt he bears was because of something that happened before the beginning. Flash reenters the speed force and witnesses again the accident that gave him his powers, before appearing in Skataris where the Warlord holds a prisoner that Flash recognises and tells to “go back before the beginning.”
Back at Barry and Iris’s wedding, Barry has Harbinger give them time to enjoy their wedding and the reception.
At the satellite, after the anti-matter wave is defeated, the heroes celebrate momentarily before Dawnstar and the heroes in the 30th century vanish as something has changed history and their future never existed.
Crisis on Earth-Prime 