Idea that popped in my head from reading some comics recently & re-watching Man of Steel. The Setting would be that of the DC universe, albeit an alternate version the players themselves have created.

In this universe General Zod, and his allies have managed to restore the shrunken city of Kandor to full size and as a result create a Kryptonian Kandorian army of individuals powered by the yellow sun. Following his lead the Kryptonians waged war on humanity & the rest of the universe taking over with ease. Superman has fallen, The Justice League has been torn apart & disbanded. General Zod reigns supreme as the ruler of the DC Universe, and the source of his victory obtaining the Anti Life Equation a formula that can remove free will & utilizing it on an unwilling all powerful ally he's come to be acquainted with named Doctor Manhattan from the DC Universe. 

Batman, aka Bruce Wayne is one of the last survivors of the Justice League 20 years into the Apocalyptic Zod influenced future. The Green Lantern corps have fallen, Zod having forged an alliance with Sinetro to have the Sinestro Corps reign supreme over his intergalatic military.  Bruce Wayne now an inter-galatic fugitive has put together a rag-tag team of recruits many former members of Young Justice & accessed a boom-tube to forge a portal through space & time to send the remnants of the resistance 20 years into the past to stop Zod's rise to power, and prevent his control over nearly all powerful Doctor Manhattan which cemented his rule over humanity & the universe.

Premise, the plot would occur in both the future & the past simultaneously. The Future Story-line focuses on Emperor Zod & his armies ruling over the universe, Bruce Wayne being arrested for sending resistance members into the past, & the resistance putting up a last ditch battle against Zod & also trying to rescue the legendary resistance fighter Bruce Wayne from his public execution scheduled in 3 weeks. 

The PRESENT storyline would focus on Zod's rise to power. In the current timeline the world is recovering from an alien invasion carried out by the vicious White Martians, Superman has been forced into retirement due to public sentiment & fear of extraterrestrials caused by the White martian invasion. The Governments of the world are pushing for regulation & monitoring of superhuman individuals across the globe due to the death toll from the 2 week long White Martian invasion which totaled 1 billion people. Wonder Woman & Batman struggle to inspire & lead the remnants of the Justice League following the casualties of the invasion, Superman's absence & the growing anti superhuman sentiments across the planet. General Zod has just managed to restore the Kandorians & escape the Phantom Zone however in the process has caused his army to be de-powered, & they are seeking out technology developed by LexCorp that can cause a a massive artificial solar flare that will empower the Kryptonian army with hte same levels of solar energy Kal-El currently has. Not only that but a mysterious visitor from another dimension who seems to have trouble follow him named Doctor Manhattan has spawned on DC earth missing his memories of his life in his native dimension.

So who's interested? We can use traditional DC characters & created characters. Future Storyline focuses on Zod already winning & running the universe, "present" storyline focuses on Zod's attempts to rise to power, the rag-tag small group of resistance fighters Bruce sent from the Future to stop Zod's rise to power.

Any interest let me know.