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A time traveler arrived in present-day Metropolis to find a piece of equipment: Skeets. He used it to summon Booster Gold. The traveler blasted Booster out of the sky, an incident witnessed by the engaged couple, Lois Lane and Clark Kent. Clark had recently told Lois about his dual identity and she was having trouble with it. He suited up to help Booster while she went out to cover the story.
As the traveler attempted to take Booster back to his correct time, Superman intervened, opening a huge time vortex. He and the Linear Man (as he called himself) were sucked in. Booster fell to the street below and told Lois Lane what had happened.
Superman awakened in the wake of an explosion. He tried to help, but was outdone by some "kids": The Legion of Superheroes. They seemed to know who he was; Superman realized he was in the 30th century and asked his own fate.

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An explosion rang out and Superman was thrust through time again, this time landing in the past (1943). A passing farmer saw him and took him to a nearby circus (because of his costume). When he awakened, his sight was a bit off from the explosion, but he saved a man from a lion who'd gotten loose. For the next two months, he traveled with and was the star attraction of the circus.
Back in the present, Booster told Lois he would find help - no time had passed since Superman disappeared into the time stream. Elsewhere, the search for Lex Luthor's heir continued.
After his vision cleared, Superman left the circus and headed to Metropolis. After saving President Roosevelt from a would-be assassin, Superman was reminded of the "mystery men" and the Justice Battalion. He flew off in search of them. Before he could enter a JSA meeting, the Spectre stopped him and sent him away so that he would not intervene.

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Superman now found himself in Nazi Germany, still 1943. He was spotted by a Nazi cargo train and reported. While there, he stopped the Nazi atomic project and saved some Jews on their way to a concentration camp. The Nazis ordered their bomb dropped, but he grabbed it and flew it into the atmosphere, where it exploded with him.

AoS 477
Somewhere in time, the Linear Man watched Superman arrive in the distant future where the Legion was faced with another Sun Eater. Superman cut through a huge sheet of ice and found a star ship. He entered it looking for oxygen and found it to be voice activated. He headed it toward the sun eater, which he'd seen from above ground.
The Legion encountered a problem with the sun eater, and Superman saved three members with his ship.
Superman and the Legion were able to destroy the sun eater, but Superman was lost. Neither the Legion nor the watching Linear Man believed him to be dead.
Time was still more or less standing still in the present.

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Superman now found himself in prehistoric times dealing with dinosaurs. By chance, he bumped into Chronos. He'd been 100 million years in the past now for 6 weeks and explained everything to Chronos. He had a plan. Chronos double crossed Superman hoping to use him as a battery to get himself home. Instead, Superman was thrust forward in time a bit to the point where mammals were emerging. He found the city state of A'r'ven. He got under one of their rockets and propelled himself forward to the time of Camelot.

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With a battle raging in Camelot, Merlin summoned Etrigan. They captured Superman, who had been enchanted by Morgaine Le Fey's magic. Merlin lifted her spell and signed Superman up for his side of the cause, promising to place him back in the time stream after the battle.
He watched Camelot fall.

AoS 478
Superman found himself on the moon in 2995. He found a Legionnaire (Laurel Gand) and saved her from a reactor explosion. The Linear Man watched and hoped Superman would be back in his own time soon. He met up with older versions of Legion members and was given a video journal of their time. A mad Daxamite from the 20th century was loose on the moon. The former Legion feared he was even more powerful than Superman.
The Daxamite, Dev-em, uncovered a secret plan when he stumbled upon some Dominators deep below the underground cities on the moon. He easily defeated them and took control of their plot to destroy Luna. He set off the countdown, but was defeated by Superman and the Legion. They also stopped the bombs. The Linear Man was livid - no explosion, no time rift. He intervened directly by confronting Superman. He told him the moon should have been destroyed, so he took it upon himself to set the future straight. The explosion, of course, sent Superman into the time stream.
After five months of time travel, Superman returned to his own time where only two hours had passed.

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Superman and the Metal Men attempted to recover the Quantum Generator while Waverider watched on invisibly. The generator exploded and time stopped. Waverider saw a woman appear and leave with Superman. He followed them into the time stream. Once their trail stopped, he found Superman and the exploding generator in a stasis field. He touched Superman and awakened the Kryptonian. The Linear Men approached them and attempted to explain things.
Superman and Waverider were returned to their time along with the exploding generator, but not before Waverider was able to snatch one of their wrist time controlling devices. Using the device, he snatched the generator and took it to the dawn of time to explode. Superman never knew what happened to it and countless lives were saved (including Matt Ryder's parents).
One of the Linear Men removed his cloak - he was the Matt Ryder of that timeline, the one who's parents survived.
Elsewhere, an immortal survived a plane crash and headed toward Metropolis.

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Liri Lee, one of the Linear Men, appeared at Justice League Headquarters and spoke with Superman and Booster Gold. Superman was warned about Waverider.
Clark and Lois attended a dinner with Pete Ross and his fiance, Lana Lang. While talking, a man at a nearby table collapsed. Time stopped except for Clark, who changed into his Superman costume. Waverider appeared and grieved - it was Matt Ryder's grandfather who'd just died. Waverider took Superman to the vanishing point - the place from where the Linear Men watched. They activated their defenses and put Superman and Waverider into stasis, but Waverider could not be held. The Matthew Ryder Linear Man revealed himself to Waverider. Waverider, now almost completely mad, killed his alternate timeline self. Upon doing so, the vanishing point vanished. They were trapped in a null sphere - time did not exist there, so they could not get out of it. Waverider touched Matt Ryder's dead body and saw his entire life. He realized his other self was much more important than what he'd become. One of the other Linear Men blasted at him with an optic device hoping to stop him from doing more damage. Waverider used the energy to connect to the time stream.
The null sphere disappeared and they all found themselves back at the vanishing point. Matt Ryder survived Waverider's attack. Waverider joined the Linear Men, and Superman was returned to his own time. Clark Kent watched Matthew Ryder's grandfather die.