Barry Allen uses his super speed to change the past, but his attempt to save his family creates a world without super heroes, forcing him to race for his life in order to save the future.
Barry Allen is struck by a bolt of lightning and thus, an extraordinary power is born inside him: The Speed Force. When he uses this power to run back in time and save his mother, he creates a world without heroes and General Zod has returned. To defeat him, his only hope rests in the hands of a retired Batman, another Barry and an imprisoned kryptonian.
Worlds collide when Barry uses his superpowers to travel back in time in order to change the events of the past. But when his attempt to save his family inadvertently alters the future, Barry becomes trapped in a reality in which General Zod has returned, threatening annihilation, and there are no Super Heroes to turn to.—Nikki D
Barry Allen has always been well-known as The Flash as he continues to juggle between civilian life and his superhero duties. However, in an attempt to save his mother from being killed, Barry travels back in time using his powers. However, whilst going back to his own universe, he is horrified to discover that he has created a timeline where superheroes are almost non-existent; this is made even worse when an alternate General Zod returns to try and destroy the world. Now with the help of an alternate and elderly Batman, an unfamiliar Kryptonian, and even his younger self from the past, Barry must stop Zod's evil plan and hopefully travel back through the space-time continuum in order to restore his universe back to the way it was.—Affan Jamsari
After helping Bruce Wayne / Batman and Diana Prince / Wonder Woman stop a robbery in Gotham City, Barry Allen revisits his childhood home, where he lived with his parents Nora and Henry, before Henry's wrongful imprisonment for Nora's murder. On the day of her death, Nora sent Henry to the grocery store for a can of tomatoes that she forgot to buy, leaving her alone in the kitchen, resulting in her being killed by an unidentified assailant. Overcome by emotions, Barry accidentally uses the Speed Force to form a "Chronobowl" and travel back in time earlier in the day. Despite Bruce's warnings of time travel's unintended consequences, Barry time travels and places the can of tomatoes in Nora's cart at the store, so that his father will not have to leave the house. As he returns to the present, Barry is knocked out of the Chronobowl by an unknown speedster and ends up in a 2013 where Nora is alive. He encounters his parents, his past self, and realizes this is the day he originally obtained his powers.
To make sure his past self gains superpowers, the two Barrys go to the Central City Police Department, where Barry re-enacts the event for 2013-Barry to be struck by lightning. Both end up getting struck by the lightning, giving 2013-Barry powers, but causing Barry to lose his own. As Barry struggles to train 2013-Barry on properly using his powers, they learn that General Zod is preparing to invade Earth.[c] In an effort to fight Zod, the Barrys attempt to assemble the Justice League but are unsuccessful; in this timeline, Diana cannot be located, Victor Stone has not gained his abilities yet, and Arthur Curry never existed. They travel to Wayne Manor, hoping to find Bruce, but instead find an alternate variant who has long retired. Bruce theorizes that using time travel to alter history affects events both prior to and after the alteration. They convince Bruce to return as Batman and help them find Kal-El / Superman.
The Barrys and Batman locate a Kryptonian pod discovered in Siberia. Upon arrival, they instead find Kal-El's cousin, Kara Zor-El, imprisoned in the facility. They rescue Kara and return to Wayne Manor. Barry enlists Bruce's help to regain his power once more. The first two attempts fail, prompting Kara to fly Barry into a storm, where he regains his powers. Kara and Batman join the Barrys to fight Zod and his forces. During the battle, Kara learns that Zod had intercepted Kal-El's escape pod from Krypton and killed him while attempting to extract the Codex needed to repopulate the Kryptonian species. Zod reveals that the Codex is actually within Kara. Zod subdues and kills her, then extracts the Codex from her blood; meanwhile, Batman sacrifices himself in an unsuccessful attempt to destroy Zod's ship.
The Barrys repeatedly time travel to save Batman and Kara but keep failing. Barry realizes that this sequence of events cannot be changed, but 2013-Barry keeps trying. As 2013-Barry travels, the multiverse starts to implode. The unknown speedster who initially knocked Barry out of the Speed Force returns and is revealed to be an older, future version of 2013-Barry who still believes he can defeat Zod and save his Earth. He becomes angry when Barry reveals his intention to reverse the changes he made to the timeline by letting Nora die. The elder 2013-Barry attempts to kill Barry, but instead impales young 2013-Barry, who sacrifices himself to save Barry and wipe his future self from the timeline.
Barry reverts the timeline and comes to terms with his mother's death; however, he subtly alters the past by moving the tomato cans to a higher shelf. Returning to the present day, Barry attends Henry's court hearing, where the security footage now reveals Henry looking up to grab the tomato can, allowing for his exoneration. Barry is then contacted by Bruce, whose appearance has changed once again as a result of the timeline alteration.
