The Button — Hive

"The Button" is a four-part crossover by DC Comics, involving Batman and The Flash. The story is building up towards the "Doomsday Clock" event.

Batman and Flash work together to find out the truth behind a bloody button found in the Batcave. The secrets of the Button bring about the wrath of the Reverse Flash and the unknown orchestrator of the DC Rebirth event.

WHAT HAPPENED BEFORE

After Flashpoint, the first Wally West was imprisoned in the Speedforce. At the end of the DC Rebirth Special, he was freed and became part of the New 52 universe.

Wally believes that it wasn't Flashpoint that caused the New 52, but something else. Someone has controlled 10 years of the DC Universe, manipulating relationships between characters that were established before that time.

In the Batcave, Batman finds the Comedian's bloody button from Watchmen, embedded in a spot where Wally's speed force lightning had struck earlier.

THE BUTTON

Batman has had no success in discovering the mystery behind the button. When he tosses the button next to Psycho-Pirate's Mask, a reaction occurs and sends a bolt of lightning into his chest.

As he recovers, Thomas Wayne, the Batman from Flashpoint, is standing before him. He abruptly fades away as Bruce attempts to reach out to him.

Batman notifies Flash, who responds by stating that he will arrive at the Batcave in "one minute". Right as the call ends, Batman hears the sound of thunder that signals Barry's arrival. But instead of Barry, Eobard Thawne, the Reverse Flash arrived. They engage in a fight, where Eobard knocks Batman out.

Thawne picks up the button and is briefly teleported away, returning with his entire body mutilated by an entity that he describes as "God" before he dies.

Barry arrives at the destroyed cave to find Bruce's injured body and Thawne's corpse. He discovers that he radiation on Thawne's corpse matches the radiation on the Button. When Batman and Flash discuss the recent events, Barry is silent about his discovery.

When Barry heads to the Justice League Watchtower, he contemplates using the Cosmic treadmill to find out who killed Thawne and is manipulating the reality of their universe.

Just as he starts running, Flash is met by Batman who wanted to continue the investigation with him.
Once the duo enters the time-stream, they are caught in a "Time Storm" where they see moments from the Pre-Flashpoint DC Universe.

When they arrive back, the treadmill got damaged. Flash and Batman find themselves inside of a different Batcave, and in the presence of Thomas Wayne Batman.

Because in this world the Flashpoint timeline was not erased, Thomas was living in the middle of the war between Aquaman and Wonder Woman. At the moment Flash and Batman arrived, Thomas was waiting for the arrival of a hit squad that was going to kill him, so he may sacrifice himself by blowing up the Batcave.
Thomas believes the two are hallucinations until the Flash briefs him on their situation.

The group works together to hold off the Atlantean-Amazonian hit squad as the Flash attempts to fix the Cosmic Treadmill. As soon as the Flash finished the repairs, Batman pleads with Thomas to come with him. Thomas pushes Batman onto the Cosmic treadmill, imploring the latter to find happiness and be the father to his son that Thomas could never be for him and to let 'the Batman' die with him.

As the Flash and Batman disappear into the time-stream, Thomas is satisfied with seeing his son alive and accepts his fate. He throws his explosive trigger away and puts his cape back on. He jumps into the white void that is erasing the Flashpoint universe. His last words are "We rise".

As Batman and Flash travel through the unraveling time-stream, they encounter Reverse-Flash, who is somehow alive. Batman notices that Thawne is still holding the button, which means that this is him right before he dies. He tries to warn him of his nearing death, but Thawne claims he already knows the source of the button's power. He charges ahead, claiming this being has never met anyone like him.

The Treadmill is breaking, and Thawne creates a shock wave sending the two flying through the Hypertime. Thawne arrives at the source of the button's energy and confronts the mysterious entity who is responsible for everything. When Thawne sees his true face, he is struck with fear and starts pleading for mercy. He is then transported back to the Batcave at the start of the story where he dies 'again'. The button got lost in the process.

As Batman and Flash get pulled into a vortex, they hear a voice calling to them. The voice tells them the only way to save them is to say his name: Jay Garrick. With a bolt of lightning, Jay Garrick takes Barry and Bruce back to the Batcave.

As Jay's body begins to unravel, he tries to help Barry remember him. Barry grabs Jay's arm, but he cannot prevent him from being transported back into the Speed Force again. Bruce and Barry did not find out who Jay really was.

When Bruce and Barry visit the graves of Thomas and Martha Wayne, they discuss their adventure and how they lost the button. They come to the conclusion that there are more unanswered questions than before. Bruce contemplates quitting Batman.

At the end of the story the button is being picked up from off the ground by the glowing blue hand of Doctor Manhattan. A familiar quote from Watchmen plays in the background:

"Why does my perception of time distress you? Everything is preordained. Even my responses. We're all just puppets, Laurie. I'm just a puppet who can see the strings."

Plot: Joshua Williamson and Tom King
Art: Jason Fabok and Howard Porter.

The text above is partly adapted from Wikipedia: https://en.wikipedia.org/wiki/The_Button_(comics)