The FlashSave

Opening sequence. Central City. Barry Allen (Ezra Miller, in their dual-role of two-Barrys throughout the film), age 26, is a forensic-evidence intern at the Central City Police Department's crime lab. He has been working overnight shifts trying to clear his father Henry Allen (Ron Livingston) of his mother Nora Allen's (Maribel Verdú) 2004 murder. Henry has been in prison since Barry was eleven for the killing — Henry was found over Nora's body holding the murder weapon, but Barry has always insisted he didn't do it. New CCTV evidence from the grocery store the day of Nora's death might exonerate Henry. The opening establishes Barry's primary motivation: undoing his mother's death.

Gotham emergency. Then Barry's STAR Labs comm goes off. The Justice League needs the Flash for a Gotham emergency. Barry runs from Central City to Gotham in eleven seconds via Speed Force. He arrives at a chaotic Gotham hospital where a Helicopter has been driven through the second floor wall, dozens of newborns are trapped in collapsing incubators, and gunmen are attacking from below. Batman (Ben Affleck, in his final DCEU appearance) and Wonder Woman (Gal Gadot) are already on scene. Barry has been brought in for emergency-extraction support. He grabs falling babies in mid-air with his time-dilation perception, runs through fragmenting hospital floors, and saves the entire neonatal ward. Wonder Woman saves the hospital staff. Batman fights the gunmen. The hospital is rescued.

Time travel discovery. Days later, Barry visits his father in prison. Henry asks Barry to give up the case. "It's making you live in the past, son. Move forward." Barry, distraught, runs along the highway at sunset. Mid-run, Barry's body accelerates past Mach 5 and into what scientists later call the Negative Speed Force — a dimensional state outside normal time. In this state, Barry can move backward through time. He surfaces at a random earlier moment of his life. He's accidentally time-traveled. He goes back home. He tests the technique deliberately the next morning. He travels back two days. Then twenty days. Then six years. Then to October 11, 2004 — the morning of his mother's murder.

The intervention. At 2004 Central City. Barry follows his nine-year-old self and his mother Nora through a grocery store on the morning of her death. He sees the moment Nora had forgotten to put a can of tomatoes in her cart — she'd gone home to start dinner without the tomatoes, then realized and asked Henry to run to the store at 8 PM to pick them up. While Henry was at the store, Nora was murdered at home. Barry — in 2023 form — silently slides the can of tomatoes into her cart. Nora notices the can. She tells Henry he won't need to go out tonight. He stays home. Barry runs back to 2023 to see the timeline shift.

Alternate 2013. Barry materializes in what he assumes is his own 2023, but he has accidentally undershot the time-jump and emerged in 2013 — the year before Henry Allen's wrongful conviction. He's eighteen years old. His mother Nora is alive. Henry is at home. Barry walks into his Central City childhood home. He hugs his mother. Then he realizes he's also in the same house with his eighteen-year-old past self (also Ezra Miller, in their other role). The two Barrys — one the time-traveler from 2023, one the original 2013 Barry — finally meet. The 2013 Barry hasn't yet been struck by lightning. He hasn't yet gotten his powers. He's just a college student.

Tutoring 2013 Barry. The 2023 Barry tutors the 2013 Barry through getting his Flash powers. They go to a STAR Labs warehouse and recreate the same lightning-strike circumstances. 2013 Barry gets his powers. Both Barrys now have Speed Force abilities. The 2023 Barry, however, has lost most of his powers — somehow, the act of going backward through time has depleted his Speed Force reserves. He can now only run at modest superhuman speed, not the Mach 5+ he had in 2023.

No Justice League. The two Barrys try to find the rest of the Justice League. Wonder Woman is missing — Themyscira's barrier is closed and Diana cannot be contacted in this timeline. Cyborg is missing — Victor Stone is still a regular human in 2013, the Mother Box accident hasn't happened yet. Aquaman is missing — Arthur Curry was never born in this timeline (or his mother Atlanna's escape from Atlantis happened differently). Only Batman remains.

Keaton Batman. The Barrys find Bruce Wayne in this alternate timeline. He's not Ben Affleck-Batman. He's the elderly Michael Keaton-Batman from the 1989/1992 Tim Burton films. Now in his early 70s, he has been retired for thirty years. He lives alone in Wayne Manor with no Alfred. He's been depressed since Vicki Vale left him in the 1990s. He's a recluse. The 2023 Barry recognizes him from old DCEU lore. He convinces Keaton-Batman to come out of retirement to help. Keaton — in his classic suit-and-bat-cowl, with a fresh suit-up sequence that gives the audience two minutes of pure 1980s nostalgia — agrees.

Kara Zor-El. The team locates a Kryptonian space-pod that crashed in Siberia. They expect to find Superman (this timeline's variant of him). Instead they find Kara Zor-El (Sasha Calle), Kal-El's cousin, kept imprisoned for years by Russian black-ops scientists in a Siberian super-secret detention facility. Kara has been chained in a chamber surrounded by yellow-sun-blocker rays. She's now in her early twenties, with the same Kryptonian abilities as Superman but with a different Earth backstory than Kal-El. She joins the team.

Zod's invasion. The same day Kara is freed, General Zod (Michael Shannon, reprising his role from Man of Steel (2013)) arrives at Earth in this alternate timeline. Without Superman to defeat him, Zod has the same plans as in Man of Steel — to terraform Earth into a new Krypton. The team (Barry, Barry, Keaton-Batman, and Kara) confronts Zod and his Kryptonian invasion force in Metropolis.

Repeated time-travel failure. Kara, attempting to defeat Zod, is killed. Keaton-Batman, attempting to defeat Zod, is killed. Both Barrys watch their teammates die. The 2023 Barry decides to time-travel back to the moment they intercepted Kara and try again with different tactics. He runs back via Speed Force. He emerges five hours earlier. He brings Kara out of the prison earlier. Zod still kills her. The 2013 Barry tries the same trick from a different angle. Zod still kills her. The Barrys try this loop dozens of times. Kara dies in dozens of variations. Keaton-Batman dies dozens of variations. The Barrys realize the universe's narrative gravity is forcing the same outcome regardless of how they alter the conditions.

Chronobowl multiverse reveal. The 2023 Barry, attempting to time-travel further and further back to alter earlier events, finally accelerates so fast that his Speed Force connection burns through into a dimensional aperture called the Chronobowl — a kaleidoscopic visualization of every possible Earth-variant timeline across the multiverse. Within the Chronobowl, Barry sees alternate Supermen, Batmen, and Earths flickering past him. The cameos include: Christopher Reeve's Superman (recreated via deepfake CGI from archival footage), George Reeves's Superman (deepfake), Adam West's Batman (deepfake), Helen Slater's 1984 Supergirl (deepfake), and live-action Nicolas Cage as his never-aired 1996 Superman from Tim Burton's Superman Lives project that was canceled. Cage's Superman is shown fighting a giant spider on a desert planet — a reference to the canceled Burton project that Smith Bros had been developing. The Chronobowl sequence is the film's most-marketed Easter-egg sequence and one of the most-litigated post-release fights between the Reeve estate, the Adam West estate, the Slater estate, and Warner Bros. for unauthorized deepfake usage.

The Dark Flash. As the 2023 Barry travels deeper into the Chronobowl, a mysterious second speedster intervenes — a faster, more-aggressive version of Barry himself who appears in the Speed Force as a black-skinned, scarred, obsessive version. The Dark Flash is revealed to be the 2013 Barry from the alternate timeline, who has been time-traveling for so long, attempting to fix his mother's death across thousands of timeline iterations, that he has become a faster, more-violent, more-obsessive version of himself. The Dark Flash is what the 2023 Barry is destined to become if he continues trying to alter his mother's death timeline. The Dark Flash is a future self warning the present self.

The choice. The 2013 Barry — still trying to save his mother — refuses to accept the Chronobowl's lesson. He keeps running. The multiverse continues collapsing. Worlds are imploding. The 2023 Barry has a final conversation with the 2013 Barry. He confesses that the act of changing one event in his mother's death cascade-collapsed the entire DCEU timeline he loved — Ben Affleck-Batman, Wonder Woman, Aquaman, all the other heroes he had known. The 2013 Barry refuses to give up. The 2023 Barry physically prevents the 2013 Barry from continuing the time-jumps. The 2013 Barry attacks the 2023 Barry. The two Barrys fight in the Speed Force. The 2023 Barry, finally, kills the 2013 Barry's possessed-Dark-Flash form to save the multiverse.

Returning the timeline. The 2023 Barry accepts his mother's death as a permanent past. He runs back to October 11, 2004. He removes the can of tomatoes from Nora's cart. He places it instead on a higher grocery-store shelf where Nora won't see it. She forgets the tomatoes. Henry has to run to the store at 8 PM as in the original timeline. Nora dies at home. Barry has accepted the loss. But the 2023 Barry has also subtly altered Henry's grocery-store CCTV footage — now Henry's face is visible on the CCTV camera proving his alibi for that evening. Henry will be exonerated. The 2023 Barry returns to the 2023 timeline. Henry is freed from prison.

Bruce Wayne's replacement. As Barry returns to his now-altered 2023 timeline, he visits Bruce Wayne's mansion to share the news of his father's exoneration. The door opens. The man standing in the foyer is no longer Ben Affleck. It's George Clooney (in his only DCEU appearance, reprising his Bruce Wayne from Batman & Robin (1997)). Barry stares. George Clooney's Batman greets him. The DCEU timeline has been subtly reshuffled — Affleck's Batman no longer exists in this universe. The film closes on Barry's startled face as he realizes the multiverse he saved is not exactly the multiverse he left.

Aftermath. Henry Allen is exonerated and released from prison. Barry returns to Central City. The DCEU has been quietly reset around him — but the major events of the previous DCEU films still occurred. He visits his now-87-year-old father. They hug for the first time in nineteen years. Cut to credits.