After a series of adventures on parallel versions of Mars, Venus, Jupiter, Uranus, and Pluto, several members of the Justice Society of America return to Earth-2: Hawkman, the Spectre, Johnny Thunder and his Thunderbolt, Starman, Wonder Woman, Dr. Mid-Nite, Sandman, and the Atom. They don't get a break from their interdimensonal hop; as soon as they return, they're called in to capture Nazi sabateurs. One of them is a scientist named Gootsden, the very one who sent them into the parallel dimensions in the first place. They find the radio that Gootsden was using to communicate with Hitler, and Hawkman sends a greeting to the Furher, telling him about all the secrets they've learned that will help the Allies. Hitler, of course, is furious and vows to have revenge on the heroes and the whole world.
Shortly after, the JSA members meet with the rest of the All-Star Squadron (except for a few absent members.) There, they see the Earth-2 Aquaman (most of the All-Star members didn't recognize him, because he apparently had never attended a meeting.) They also meet up with Mekanique, a female robot claiming to be from the future. She had earlier warned them about an accident that would take place, so Green Lantern and All-Star member Firebrand had stopped the accident, and saved a little girl and an admiral. Firebrand apologizes for having been suspicious of Mekanique's motives. The robot claims she's not offended, and even agrees that one has to be cautious when dealing with the future.
The All-Star members then assemble to take a group picture. The Earth-2 Batman is reluctant to have his photo taken. This shouldn't be surprising; after all, he is the Dark Knight and likes being behind the scenes. But he goes along with it, and even smiles for the camera. He comments that some of the All-Star members are missing, mainly "Plastic Man and a few others."
Firebrand explains their absences: Uncle Sam (the living embodiment of America's patriotic faith, incredibly strong after the Japanese attack on Pearl Harbor only months earlier,) Plastic Man, Doll Man, The Ray, Black Condor, Phantom Lady, and the Human Bomb have gone to the parallel world of Earth-X. On that alternate Earth, she claims that "our side is in danger of losing to Hitler, Tojo (the general in charge of Japan's army,) and the others," implying that the Axis powers are having better success than they are on Earth-2. Firebrand tells them that they probably won't see these heroes for a while. That turns out to be prophetic. Those six heroes, who are known as the Freedom Fighters, have to fight the Axis Powers for another 40 years. (Imagine the pensions they would have been entiled to!)
After taking the group photo, All Star member Robotman (who has developed a close bond with Mekanique, and obviously has feelings for her) and Mekanique take a walk outside the All-Star headquarters. During their conversation, he asks her about the name "Rotwang." She claims not to recognize the name, but Robotman tells her she spoke it when he first found her. He then hypnotizes her, and learns a terrible truth: Rotwang is an evil dictator in her time, and is her creator. In her time (later revealed to be the 23rd Century,) a woman named Maria leads a successful rebellion that overthrows Rotwang. Mekanique is sent back to prevent Maria's existence, and therefore prevent the rebellion.
Robotman is confused, because he points out that Green Lantern and Firebrand had saved the little girl and the admiral that would have died in a car accident. He then realizes that that was part of Mekanique's plan: the two were supposed to die, in order for the rebel leader Maria to lead the rebellion. By saving the admiral and the girl, the heroes thought that they were saving the future, when they were in fact unwittingly destroying the future with a victorious Maria.
Before he can react further, Mekanique has another disturbing revelation: through Rotwang's scientific know-how, she has single-handedly prevented an event known as the Crisis on Infinite Earths from finalizing in the All-Star's time period (May 1942.) She releases whatever forces were preventing the changes, and this causes Earth's history to be altered. No one in the past, present, or future is aware of these changes taking place.
[The Crisis on Infinite Earths was a 12-part series that involved nearly all of DC Comics' characters, and it was published in 1985. During the series, a villain known as the Anti-Monitor destroys most of the positive-matter parallel universes. Heroes from the five remaining positive-matter universes, along with some from the destroyed parallel Earths, battle the Anti-Monitor at the beginning of time. This alters history, and prevents the creation of the multiverse. The heroes find themselves in the present, on a single Earth. In a final, climactic battle, they fight the Anti-Monitor in his own anti-matter universe. The Earth-2 Superman delivers the final killing blow (throwing an entire moon on him, and then punching him into a star.)]
The changes in the timeline disorient Robotman, and he completely forgets the part of the conversation where he learns the truth about Mekanique. She then continues their previous conversation, as if nothing happened. But something has happened, which is obvious to the reader: the skies, which had been red, are now blue again. More changes are to become evident. The final scene shows President Roosevelt meeting with Hawkman, admiring the photo of the All-Stars taken earlier. Hawkman tells the president that some of the members couldn't make it, but that the majority were there. Roosevelt dismisses Hawkman's apology, saying that anyone not in the photo "must be someone so obscure that nobody ever heard of them!"
The last panel then shows the photo, with some drastic alterations to how it appeared earlier: Superman, Wonder Woman, Batman and Robin are missing. In their places are Uncle Sam, Plastic Man, Doll Man, The Ray, Black Condor, Phantom Lady, and the Human Bomb. It's now obvious that the changes wrought by the Crisis have taken effect. Earth-2 has ceased to exist in 1942, and so have the Earth-2 versions of Superman, Wonder Woman, Batman and Robin.