What is it?
The 2021 director’s cut of the 2017 American superhero movie Justice League, called Zack Snyder’s Justice League (Snyder Cut).
Here is how Wikipedia describes this movie:
Zack Snyder’s Justice League (colloquially referred to as the Snyder Cut) is the 2021 director’s cut of the 2017 American superhero film Justice League, the fifth installment in the DC Extended Universe (DCEU) and an immediate sequel to Batman v Superman: Dawn of Justice (2016), presented the way originally intended by director Zack Snyder prior to departing the production. Like the theatrical release, it follows the DC Comics heroes Batman (Ben Affleck), Wonder Woman (Gal Gadot), Cyborg (Ray Fisher), Aquaman (Jason Momoa) and The Flash (Ezra Miller) as they form an alliance and are joined by a revived Superman (Henry Cavill) in an attempt to defeat the interdimensional conqueror Steppenwolf (Ciarán Hinds) and his army of Parademons.
Here is how The IMDb describes this movie:
Determined to ensure Superman’s ultimate sacrifice was not in vain, Bruce Wayne aligns forces with Diana Prince with plans to recruit a team of metahumans to protect the world from an approaching threat of catastrophic proportions. The task proves more difficult than Bruce imagined, as each of the recruits must face the demons of their own pasts to transcend that which has held them back, allowing them to come together, finally forming an unprecedented league of heroes. Now united, Batman, Wonder Woman, Aquaman, Cyborg and The Flash may be too late to save the planet from Steppenwolf, DeSaad and Darkseid and their dreadful intentions.