max lord and talia al ghul are the black king and black queen for checkmate, the government agency. they have a mutual agenda against caped heroes. talia's reasons for despising super heroes is ambiguous, but there are some vague references to her father and his ideals. max's reasons are far more defined: a couple years ago his fiancee was caught up in a battle between superman and metallo, she lost her life. he's since seen heroes as a plague that need to be exterminated. this is one of the reasons he creates the OMACs. he plans to use them to rid the world of super heroes, since the robots can be the perfect policing unit which can also be controlled by the government and work for their agenda. he is even going head to head against lex luthor for the contract, who has created similar technology. max also plans on using the OMACs for his own personal agenda...believing that checkmate should be running the government, a sort of coup would put him in power. the OMACs will also be using human hosts, the technology takes over the body. max lord plans on using heroes as host bodies to result in stronger OMACs (a superman omac being the big prize). theres even a few scenes planned for early on in the film where OMACs take over b-list DC characters, fun cameos for the fans. at one point in the film, even flash and GL will become OMACs.
the JLA will consist of: superman, batman, wonder woman, flash (wally), green lantern (jon), aquaman, and martian manhunter. there will be a bunch of humor earlier on at their headquarters showing what heroes do when they are bored with no crime to fight. meanwhile, batman is off investigating heroes that have been picked off by OMAC's.
anyways, a group of shape-shifting white martians travel to earth and find max lord, well aware of his status in the government (it would appear white martians have a past with checkmate). they ask for refuge on earth to escape an aggressor who is at war with them. max denies them, knowing they will then invade earth and take refuge anyways (how he knows this and why he wants it will be later revealed). the white martians leave very angry and sure enough make plans to invade earth.
as the martians invade, the heroes come out, and so do max's OMACs. this is max's chance to prove to the government their worth and how much better they are than the super heroes. the fight against the white martian invasion will be the chunk of the film. during this time, the heroes become very aware of max lord, his story, and his agenda. they come into direct conflict, and more is revealed about him. about half way through the film, it will be revealed that max is a shape shifting white martian himself (not even the other martians knew this), but he was banished from the white martian community long ago which is when he traveled to earth. also, he's not only been disguised as max lord infiltrating the american government plotting a take over...but he's also been disguising himself as JLA member martian manhunter! working to infiltrate the heroes, learn their secrets, so he can eventually take them down using the OMACs. enraged at his betrayal, wonder woman snaps his neck, killing him! breaking the league's no killing policy. she stands behind her actions against a very pissed off batman and superman. still fighting the invasion, batman ends up being able to reprogram and take control of the OMACs and they use them to defeat the martian invasion.
but in the last 20-30 minutes of the film, a new threat will arrive. its the agressor that has been at war with the white martians. they have followed them to earth. its darkseid! darkseid and his army finds the white martians defeated and a new challenge in the JLA. the JLA goes to battle with him and his personal cronies, while his army attacks the country. in battle with darkseid himself, superman is killed! now regretting her actions, and recognizing superman's heroism, wonder woman begs her gods to take her life force and spare superman's. her gods comply. wonder woman dies, and superman is revived. he single handedly takes out darkseid. the heroes are overwhelmed by the rest of his army though. lex luthor appears on scene with his tech army (the one he was using to get the government contract against max lord). together they stop the invasion.
