Last year, DC changed their comic continuity with Rebirth. The one-shot issue brought the characters back to their core, while alluding that something or someone more powerful was behind the alteration to the universe: Doctor Manhattan from the critically acclaimed book Watchmen.

Now, DC is giving readers some answers to the questions that have been plaguing their minds since last May. The Batman/Flash crossover story The Button kicks off in Batman #21.

Batman and The Flash team up to learn more about the mysterious button--once owned by The Comedian--which is embedded in the walls of the Batcave. However, Reverse Flash is also a part of this mystery, as seen in the preview above.

DC has been tight-lipped about the four-part crossover, which will take place in Batman #21-22 and Flash #21-22. The publisher released a solicitation for the story but nothing else: "What starts as a simple investigation turns deadly when the secrets of the button prove irresistible to an unwelcome third party—and it's not who anyone suspects. It's a mystery woven through time, and the ticking clock starts here!"

Writer Tom King will continue his run on Batman with artist Jason Fabok and colorist Brad Anderson for the upcoming story. Batman #21 will go on sale on Wednesday, April 19 available at comic shops and digitally.