Thanks to Simon Carr, the files kept by J'Onn J'Onzz at the Sanctuary were available to exploit. The Appellaxian invaders struck Earth's metahuman community hard and fast, exploiting their knowledge of secret identities and other vulnerabilities. "First, they took Superman." The Atom, Blue Beetle, the Metal Men, Batman, Hawkman, Johnny Quick, and Dr. Mid-Nite followed in turn. Setting up an internment camp on Blackhawk Island, members of the Squadron, the Freedom Fighters, Seven Soldiers of Victory, and the Justice Society could all be seen as being held captive. As the only files removed from the piles were those belonging to Barry, Dinah, Hal, and Arthur, they were the only heroes spared.
The Justice League were in Metropolis, fighting a tiny portion of the 7,000 or so Appellaxian proxy bodies alerted to the threat Earth posed, intent on wiping us out. Aquaman was randomly shouting orders to the team while discussing with Snapper Carr how Uncle Simon's Appellaxian, Kalar, evaded Martian Manhunter's telepathy by loosening his psychic grip as needed. Simon was barely aware of any changes to his consciousness. Martian Manhunter had only just caught a falling Green Lantern when he soon after took another tumble, thanks to a depleted power battery. After over 24 hours of continuous fighting, the League was broadly tapped out, but not so much that the Alien Atlas couldn't guide the Flash to a locker at Ferris Aircraft housing an invisible power battery. The Emerald Gladiator was soon speaking his oath to recharge midair. Aquaman congratulated the crackerjack teamwork, but also had to acknowledge that Metropolis was lost to the invaders.
In Gotham City, Kalar needlessly obliterated the mind of an Appellaxian fire proxy to take it as his own, surrendering Simon Carr's frail human form. Just as he'd sent the soldier to the plasmgods above, so to had he planned to execute Carr. However, he was spirited away by Vandal Savage, along with the device Kalar had used against his own kind. Meanwhile, things faired just as poorly for the League in Midway City, though Barry scored a kiss from Dinah in a moment of weakness. The Scarlet Speedster had wondered aloud "What... would the JSA have done," but suddenly struck upon his own inspiration.
Via the undervalued "talks to fishes," Aquaman knew where in the Atlantic Ocean the metahumans were being held. Almost as soon as the League arrived back at the sanctuary, they were captured by Appellaxians exploiting their specific vulnerabilities. Soon, the League was on Blackhawk Island, and Green Lantern was warned not to try anything, or his yellow bonds woukd squeeze the life out of him. A demonstration was provided, and Lantern screamed in such pain that it blew a hole through an Appellaxian's chest. "His" power ring had disguised the League as one another, so that Black Canary easily brushed off Lantern's bonds, while Hal Jordan was hardly bothered by a cage of fire, and so on. Soon, Flash had recovered all the heroes' stolen technology, which was being studied by the invaders ahead of their planning to do the same to the metahumans. Suddenly, the prison camp was becoming the staging grounds for the super-human resistance army...
"Stalag Earth" was by storytellers Mark Waid / Brian Augustyn / Barry Kitson with inker Michael Bair. It will never not drive me nuts that DC went decades pretending like everyone from the JLA to Speedy were active before Robin the Boy Wonder just because of stupid "Batman: Year Three." Real time, the Dark Knight flew solo for one year and one month, but editors and dirtbag fandom keep trying to erase one of the greatest characters in all of comics because grimdark. Don't even get me started on Wonder Woman. Anyway, it's always fun to see heroes get took, and leaving them behind fences has a resonance today following Gitmo and refugee detentions that may have been fuzzier to readers in '98 over a half century removed from the Japanese internments of World War II. Seeing these costumed prisoners of war liberate themselves might have had more "oomph" broken up by a cliffhanger, but the resolution was appropriately clever and Silver Agey for a series rooted in nostalgia. Neat to see so many heroes from across DC's history all in one place, centering on their first couple of decades so that we're not suffering any Infinitors or New Bloods or whatever. It's also fun because of how many DC acquisitions are present, published by different companies in the beginning, with few integrating into the DC Universe until the 1970s. It's the sort of thing children of the Greatest Generation could scarcely dream of when they were all publishing contemporaries.