DC Comics Presents #1 (1982)

Superman and the Flash are both returning to their home cities following missions out of town. As they both pass through the small town of Rosemont, they spot a strange vibrational ray striking the town from space and both attempt to stop it. When the Man of Steel tracks it to a strange spaceship, he attempts to approach it but it explodes. Elsewhere in the town Flash sees that the strange vibrational ray is causing the townspeople to start to shift into another dimension. Spotting each other, the two heroes work together to prevent this from happening. While the Flash races around the city to maintain its vibrational alinement, Superman ushers the people out of the town and then uses his indestructible cape to prevent the beam from striking the town. He then follows the beam to its source, a massive spaceship locked in combat with another shuttle. Superman scans the ship with his x-ray vision and is shocked to find that it is organic in nature. As Superman attempts to stop the two warring ships, both he and the Flash are trapped in strange energy spheres and are brought aboard a drydock between the two ships. With Superman trapped in a cage using Q-Energy to keep him prisoner and the Flash in a cage that counters his vibrational ability they are confronted by two aliens named Aylem and Islan members of the Volkir and Zelkot races. The two aliens explain that they come from warring societies that have come from similar evolutions that have been locked in an intergalactic war for centuries. They explain that a rogue scientist of the Zelkot, Iylar had stolen a time travel device and came to Earth with the hopes of travelling to the past and stopping the evolutionary divide and prevent the civil war from happening. They explain that the Volkir and Zelkot evolutions also helped create life on Earth, and preserve a certain planet near a red sun, and that they intend on stopping Iylar from succeeding in his mission. Part of this plan also involved capturing both Superman and the Flash as they would be the only two men who would stand in their way. Superman and Flash would break out of their cages and attempt to stop the aliens when it's pointed out that if Iylar succeeds the human race would never exist. Ceasing their battle, Superman and the Flash offer their services to help the two alien races stop Iylar. They show the two heroes that their time travel technology only allows them to travel forward into the future and that Iylar is intending to travel to the end of time because, in theory, time is a constant loop. In reaching the end of time, Iylar hopes to pass through a rift back to the beginning of time, allowing him to travel to the point where he can stop the precursor of the Volkir and Zelkot into evolving into two different species. Noting that the Flash is faster that Superman, they equip him with a communicator device and send him back down to Earth where Flash uses his speed powers to travel forward into the future in the hopes of stopping Iylar. As Flash speeds into the future, he has the unfortunate luck of running into his old enemy the Reverse-Flash who was just then speeding back in time to commit crimes in the 20th century. Causing them both to collide in the 25th century and knocking out the Flash. Watching this from the 20th Century, the leader of the Zelkot's tries to convince Superman to continue forward into the future and insure that the Zelkot's exist. When Superman refuses, they point out that if the Zelkot's cease to exist the planet they briefly inhabited: a certain red planet would build up atomic pressure and explode centuries before it was destined to. Superman realizes that the planet they are referring to is Krypton and his continued existence would be at jeopardy if history were changed. Superman would then speed off and travel through the time barrier seeking to stop Iylar even if it meant preventing the human race from ever existing. While in the 25th Century, Flash revives and is disoriented from his collision with Professor Zoom. The Reverse-Flash takes advantage of this to knock Flash out again, vowing to kill his old enemy once and for all.