When DC Comics released its "DC Universe: Rebirth" in May 2016, the publisher laid the groundwork for a new continuity that reintroduced long-absent characters and paved the way for the potential return of teams like the Legion of Super-Heroes and the Justice Society of America. However, the key revelations involved Wally West, missing time and the possible behind-the-scenes involvement of the Watchmen.

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Following months of clues and questions, those mysteries will be addressed head on next month in "The Button," a four-part crossover involving "Batman" and "The Flash." While DC revealed some intriguing lenticular covers for the event last month, the publisher has now debuted the remaining covers for "Batman" #22, the third chapter in the storyline.

Batman #22 by Jason Fabok
Batman #22 by Jason Fabok

The two covers -- one by Jason Fabok and the other by Tim Sale -- tease the return of Thomas Wayne as the Batman, his first appearance in that role since the events of "Flashpoint." In that alternate timeline he assumed the costumed identity following the murders of his wife Martha and son Bruce.

Batman #22 by Tim Sale
Batman #22 by Tim Sale

"The Button" begins in April in "Batman" #21 and "The Flash" #21, and concludes in May in "Batman" #22 and "The Flash" #22. The "Batman" issues are written by Tom King and illustrated by Fabok, with "The Flash" by Joshua Williamson and Howard Porter. All four issues will feature lenticular covers by Fabok.

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The story explores the mystery of how The Comedian’s blood-splattered smiley face button from “Watchmen” appared in the Batcave at the end of  “DC Universe: Rebirth” #1. It was the first time elements from Alan Moore and Dave Gibbons’ seminal “Watchmen” have appeared in the DC Univers.

Here’s DC’s official description for "The Button":

Two greatest detectives in the DC Universe unite to unravel the mystery behind a certain blood stained smiley face button stuck in the Batcave wall. However, what begins as a simple investigation soon turns deadly when the secrets of the button prove irresistible to an unwelcome third party — and it’s not who anyone suspects! This is a mystery woven throughout time, and the countdown starts here!

“Batman” #22, by King and Fabok, goes on sale May 3.