All-Star Comics #49 (1949)

A comet passes by and strange meteors land across the country. Like clockwork, fires erupt nearby all the landing sites at the same time. The Justice Society decides to look into this, only for one of the meteors to land right outside their headquarters. They notice the outline of a door, but after they cool it with water the meteor shrinks into insignificance. They seek the input of a Dr. Conrad into this fantastic problem, and he reveals a bizarre film recording he found through uranium emissions: a million years ago Earth was home to a super-advanced society, and the man who made the recording on the uranium warns the world of the future of how they were wiped out by flame-men who came from meteors dropped by a comet. Noticing the pattern is identical to the one facing the world now, the Justice Society splits up to investigate all the meteor landings. The Atom and Black Canary visit Palomina Unversity which is one of the country's biggest stockpiles of Radium, which the flame people stole before. Sure enough the flame people arrive to plunder it, and the terrible heat they give off forces the heroes to retreat in defeat. The Flash and Dr. Mid-Nite track another group of flame people to another radium stockpile, and have better luck by thinking to use asbestos suits. However they're also defeated when flame people pull off their hoods from behind while another melts open a jar of ether and the fumes knock them out. Hawkman and Wonder Woman stake out one of the biggest uranium-refining plants in the country and run into a group of flame men, who use their heat to evaporate a pool of water and create a blanket of steam to cover their escape. On his own, Green Lantern finds where the flame people are building their escape craft, and is attacked by a group of them. His ring protects him from their heat, but the heat they give off also acts as a buffer keeping his beam from overcoming them. They unleash a powerful radium gun, starting to work through even Green Lantern's protective powers, forcing the emerald crusader to retreat. The army soon arrives in response to Green Lantern's warning, but are unable to defeat the flame men either. Dr. Conrad is convinced that the human race is about to die from the radioactive exhaust left by the flame people's escape craft, just as it did a million years before. He's carving a warning into a rock face so that future generations may know of the danger of the flame men, but the Justice Society interrupt him and ask for a certain scientific apparatus to carry out one last-ditch plan. The JSA attack the flame people with carbon arc projectors, which give off even greater heat than the flame people themselves. They came up with the idea when they remembered the old saying "fight fire with fire". Beaten by their own main attack, the flame people turn one of their radium guns on themselves and commit suicide rather than be captured. The comet will return in another million years, but now Conrad's message tells humanity how to defeat the flame people the next time the invasion comes instead of to await their doom.