Here's the FULL plot for Justice League: Mortal:
The movie would be set in the same Universe as "Batman Begins" and "Superman Returns".
It'd begin with Superman, wearing a black and silver costume, landing on the rooftop of a church, where he meets with Wonder-Woman, the Flash, Green Lantern, Aquaman and Martian Manhunter. Together, they descend into the streets, where they are surrounded by civillians and journalists as they enter the church, where a funeral is being held. Batman watches them from a affar.
Six days before, Batman, using a state-of-art surveilliance satellite called Brother-Eye, spies on the other members of the Justice League: Clark Kent, Diana from Themyscera, Barry Allen, John Stewart, Arthur Curry and John Jones.
After Batman leaves for a meeting with Maxwell Lord under his civillian identity, the Bat-computer in hacked by a outside source, that uses Brother-Eye to resume spying on John Jones, a police detective from Central City.
John receives a package and, upon opening, a swarm of nanobots is sprayed on his face. They enter his body and take over his movements, forcing him to reveal himself as the Martian Manhunter to his co-worker before making him fly to a certain location in Colorado.
Barry Allen spots him and attempts to follow him as the Flash, but fails. Upon arriving in Colorado, J'onn is captured by mysterious forces.
As the Justice League investigates Martian Manhunter's disappearance, Batman finds out Brother-Eye has been compromised and that the files he kept on how to defeat each member of the Justice League have been stolen.
Those files are uploaded on the OMACs, advanced cyborgs that take over ordinary people trough a nanovirus. The OMACs are send to destroy the Justice League, while a mysterious enemy uses the nanobots to take over Martian Manhunter's powers and use his telephaty to take over Superman and force him to kill Batman.
Wonder-Woman and Batman engage in a powerful battle against Superman, while Green Lantern and Aquaman fight the OMACs send after them and the Flash's investigation leads him to a castle in Belgica, where he is murdered by the mastermind behind the attack after finding J'onn. The mastermind is not one, but two: Maxwell Lord and Thalia Al Ghul.
Lord believes that the superheroes are taking over the world and changing the natural course of history, and wants to destroy them to "save the world", whereas Thalia, the new leader of the League of Shadows, wants revenge for her father's, R'as Al Ghul, death at the hands of Batman years prior.
They have created the OMAC virus with the help of an outside source and use the OMACs to attack the Justice League.
Batman finds Lord's hideout and Wonder-Woman snaps his neck to release J'onn and Superman from his control. Thalia fights Batman and is defeated, but the Justice League now has to deal with the OMAC army and the real mastermind behind it's creation: Lex Luthor.
Using a powerful EMP generator created by Wayne Industries and aided by the former Kid Flash, Wally West, now the second Flash, the Justice League defeats the OMACs, but Luthor gets away with his envolvement in all of this.
Batman leaves the group, Wonder-Woman receives murder charges and Wally decides to join the Justice League and honor his uncle's legacy. At the ending, it is revealed that there was a fouth villain envolved in the conspiracy: Darkseid, who is planning a invasion to Earth, setting up the sequel.
Warner hired George Miller to direct the movie and planned to have a big ensemble cast, with Brandon Routh as Superman; Christian Bale as Batman; Jessica Biel as Wonder-Woman; Anton Yelchin as the Flash; Columbus Short as Green Lantern; Leonardo DiCaprio as Aquaman; Lawrence Fishburne as Martian Manhunter; Scarlett Johansson as Thalia; Mel Gibson as Maxwell Lord and Kevin Spacey as Lex Luthor.
However, Christopher Nolan felt that the movie would damage the image of the sequel of "Batman Begins", "The Dark Knight", already in production.
To prevent this, Warner decide to rewrite the movie as of not being connected to the Nolanverse. This, allied to the fan backlash and the expensive taxes charged by the Australian government, led Warner to settle for a lesser cast, with D.J. Cotrona as Superman; Armie Hammer as Batman; Megan Gale as Wonder-Woman; Adam Brody as the Flash; Common as Green Lantern; Santiago Cabrera as Aquaman; Hugh Keays-Byrne as Martian Manhunter; Jay Baruchel as Maxwell Lord and Teresa Palmer as Thalia Al Ghul.
Miller decide to rewrite the movie by himself, making it a gritty, bloody, almost "Watchmen"-like tale that dwelved deeply into the Justice Leaguers troubled psyches. Warner decided that it was just not worth it to continue with the project and interrupted the production two weeks before filming began. Sets, props, costumes, storyboard and Animatics had already been done by the time.
The Justice League's headquarters would be the Hall of Justice in Washington, D.C., designed by Diana and John Stewart and funded by Bruce Wayne.
The Fortress of Solitude, the Batcave, the Themyscera embassy, Barry Allen's house, the Atlantis throne room and Maxwell Lord's mansion/headquarters would be heavily featured.
Superman's costume was all blue except for gold belt and red cape, and had Kryptonian lettering etched into its fabric, a digital print along his arms, like electronic data. His belt had fine detail that told the story of how he landed on earth.
Batman's suit was all black, more like a black-ops military soldier. Very bulky, solid and practical. He carried tools on his belt, like batrangs, hooks and gas grenades. Not as futuristic or sleek as the Nolan one.
Wonder Woman's armor was realistic, ancient Greek warrior, with leather bodice and a battle-skirt with greek symbols on the belt. No stars, stripes or spandex of any kind.
Flash had a classic suit - full red bodysuit, flash logo on chest, runners, the golden ear wings were smaller, and went straight back instead of outwards.
Green Lantern had the classic John Stewart version of the uniform, but more alien and organic-looking.
Aquaman had the modern look - long hair, green scaly tights, golden armor, but assymetrical, so his left shoulder was exposed. His left hand had a harpoon attachment.
Martian Manhunter used his original martian form troughout the movie.
Iris West would be heavily featured in the movie and Zoe Kazan was cast to play her. There were also rumors about a certain Dr. Patrick O'Brien, played by Bob Saget. You must remember that that's Plastic-Man's secret identity.
Further rewrites of the movie had the Justice League's origin being told, but still featured the OMACs and the League of Assassins. Further rewrites also had R'as Al Ghul, in the classic immortal eco-terrorist version, play a major part alongside Max, Thalia and Lex.
