The Thanagarian Invasion
The first idea is a cheat as it’s a storyline from the Justice League animated series. The Thanagarian Invasion is the final arc in the original Justice League before it branched into Justice League: Unlimited. It tells the story of a warrior race who come to Earth with the idea of helping them against a more deadly enemy.
The Justice League is already aware of the Thanagarians since one of their members, Hawkgirl, is one of them. Batman discovers the Thanagarians are actually trying to take over the Earth, and when their plans come to light, Hawkgirl betrays the Justice League.
The Justice League finds themselves underground and sheds their superhero identities. It also features a great moment where Batman outs everyone’s identity, including his own.
In order to do this story, a coherent universe needs to happen. It should include a Green Lantern, Martian Manhunter, and Hawkgirl. Thankfully, rumors say Dwayne Johnson’s upcoming Black Adam movie includes Hawkgirl.
A Green Lantern series, and movie, are on their way but there’s no sign of the Martian Manhunter appearing anytime soon.
Apparently, that would have happened in Zack Snyder’s original Justice League cut but we will never know.
The Thanagarian War works better as a two-movie event. The first movie introduces the Thanagarians and their plan to help Earth. Around halfway through the twist comes into effect where the Justice League finds out the truth.
To make matters worse, the American Government wouldn’t believe the League and brand them as traitors.
It wouldn’t be until close to the end of the movie where the Thanagarians reveal their true intentions to the world. The first movie would end with the Justice League imprisoned by the Thanagarians and the Earth being left with no defense.
The second movie focuses on the Justice League’s escape from the Thanagarian ship, them going underground, and building a rebellion to go against the Thanagarians.
The great thing about the storyline is the emotional impact it’ll have. There’s betrayal, a rollercoaster of twists, and one of the Justice League could sacrifice their life to save the Earth. This would create a fallout in the following movies and sow the seeds of distrust among the League and the Government.
