The armies of Mars rise against the unsuspecting population of Earth—and only the combined might of the Justice League and the Legion of Super-Heroes can stand against them.

Visionary writer Jeff Lemire (GREEN ARROW, ANIMAL MAN) and artist Neil Edwards (FOREVER EVIL: A.R.G.U.S.) bring together two teams of heroes from across centuries: Martian Manhunter, Green Arrow, Supergirl, Animal Man, Stargirl, Equinox, and Alanna and Alan Strange—together they are the Justice League United. They've barely been together long enough to consider themselves a team, and already they're faced with a threat that could destroy all of space—and time. A group of time-traveling crusaders called the Legion of Super-Heroes has suddenly appeared on the JLU's doorstep with a dire warning: Ultra, the multi-alien hybrid the team just rescued from the mad Thanagarian shape-shifter, Lord Byth, has a future of doom and destruction ahead of him. The Legion has come back to stop young Ultra before he ever gets a chance to become Infinitus, annihilator of worlds! Though this devastation won't happen until the 31st century, the Legion believes they can prevent it in the present day. Little do they know that their presence out of time will only accelerate the course of events—and that fits perfectly into Byth's master plan! Collects: Justice League United #7-10, Annual #1, Futures End #1 and Justice League Futures End #1.