Just over half of those are familiar faces to readers of the Image series - Ultiman, Thunder Girl, and the Knight Watchman. The rest (and you can figure out who is who pretty easily) are Venus, the Blitz, and the Beacon, ersatz Wonder Woman, Flash, and Green Lantern respectively.
Dr Stellar, obviously the Starman of the KoJ, wonders how the team came to be. The Knight Watchman lays the background by saying it all started when scientists from around the country were headed to the Great Minds Summit in Washington, D.C. The Blitz takes over from there, and it becomes clear that this issue's gimmick is just like the earliest JSA stories -- the heroes don't really work together, but they tell of adventures that are connected in some way. Naturally, each segment is handled by a different writer and artist. I wish they had a Hawkman guy, since Golden Age Hawkman had unusually detailed art for its time and I'd love to see something in that style.
Now, if I'm remembering correctly, the Flash section of the JSA story I'm thinking of involved fighting a shark, so one can only hope it's something half as cool as that.
Anyway, the Blitz is secretly newsreel reporter Mack Snelling, who was on his way to cover the summit via the powerful train Super-Chief. A freak landslide nearly causes a horrible crash, but Snelling clears the way with time to spare as the Blitz, and soon discovers it was a Nazi assassination attempt on one of the train's passengers, engineer and auto magnate Hank Fort.
An interrogation reveals that this was part of a larger plot to sabotage the Great Minds Summit. The Blitz heads back to Super-Chief, no doubt reasoning that if there's more trouble at the conference he should be there (and that arriving before the train he was on previously would probably blow his identity).
The Beacon takes the story from there. He'd read about the Great Minds Summit in the paper back in NYC, when he was on a ferry to Ellis Island. Due to some trouble at the Statue of Liberty, they had to turn back, but naturally this looked like a job for the Beacon. It turns out there's some kind of DEATH RAY coming out of Lady Liberty's torch, blasting boats as they pass. The Beacon does rescue work to ensure that nobody dies, using the light from his miner's cap to escort people to life rafts and seal holes in hulls.
Golden Age Green Lantern's powers were so nebulously defined as to be nearly limitless; I remember a story in Batman Black and White where he mentioned he quit the superhero game because he felt too powerful, and Gotham needed a hero, not a god. The Beacon is more like Space Ghost, in that his light fires different beams for different occasions -- a tractor beam, a heat ray, that sort of thing.
After turning the culprits in, the Beacon meets with the captain of the ship he saved, as well as a notable passenger, famous inventor Tom Ettleson. The Beacon escorts Ettleson's car to Washington to make sure he arrives safely, and that's when his part of the story ends and the Badge's begins.
This seems as good a time as any to mention that Rookies, Bobbie and Trooper, are nowhere to be seen -- implicitly this takes place before their first appearance.
This is all introduced in a clumsy enough way that I'd have trouble describing it succinctly, so the gist: the Badge, staking out a local slum, meets a man who falls unconscious and is taken away in an ambulance by a rude German medic. Various clues reveal the man's identity as Dr. Reinstein, a famous scientist bound for the Great Minds Summit, and that he had been drugged. The Badge also guesses that the German medic is evidence of a Nazi plot. He commandeers a police bike, catches up to the ambulance, and jumps onto its roof, forcing the driver to crash.
Citizen's arrest? So he's not really cop? Well, I guess the Knight Watchman isn't a real knight, either. The Badge frees Reinstein from the ambulance, but one of the Nazis steals Reinstein's briefcase, which contains a top-secret formula. The Badge does something I didn't really expect him to for some reason -- he throws his shield, nailing the Nazi thief in the back. The Badge then accompanies Reinstein to the summit to guarantee his safety.
On to Thunder Girl, who, like the Blitz, was already on her way to the summit in her secret identity. In this case, it was with her friend Dr. Eureka and his colleague Dr. Igorski, in their latest invention -- an electric gyrocopter. They're accosted by a massive Nazi zeppelin, housing soldiers open fire on them. Molly turns into Thunder Girl, who covers the scientists' escape and takes care of the blimp with a simple hairpin.
See, that was simple. These are three page stories, that Badge one was so dense and overwritten (although that might have been intentional for all I know, that's kind of the point of Big Bang). Anyway, she naturally follows the copter to Washington.
The Knight Watchman's story begins as his wrist-mounted "Watch-Alert", which is evidently like the Bat-Signal crossed with Jimmy Olsen's signal watch, goes off just after he's finished his nightly patrol. Dr. Igor Eisner, a friend of the Knight Watchman's who appeared in a previous story, reports a break-in at his lab -- by Nazis, as you can no doubt imagine.
After reaching the scene in the Watchwagon, the Knight Watchman fights his way through Eisner's home to discover the scientist isn't there. It turns out he's being transported to Germany. Thinking quickly, the Knight Watchman rifles through Eisner's inventions to find a rocket pack he'd tested just a week ago
He soon finds them, rowing out to a U-Boat. Attacking the U-Boat with a grenade, the Knight Watchman scares its crew into submerging, leaving Eisner's captors literally high and dry. Eisner is rescued, and naturally the Knight Watchman accompanies him to the summit in case there's any more trouble.
Venus takes over. It turns out she's literally the goddess Venus. So, she was in Philadelphia (which might be her normal stomping grounds), escorting the French chemist Madame Furie to the summit. Furie looks little like the real Marie Curie, who was kind of emaciated; instead she looks like Wonder Woman's Golden Age pseudo-sidekick Etta Candy.
Venus and Furie are visiting the Liberty Bell at the moment, where they're surprised by a Nazi spy known as the Temptress. Via a weirdo gun, the Temptress gets the Liberty Bell to ring, a sound so cacophonous it knock Venus and Furie right out. When Venus comes to, she sees Furie being taken away by the Temptress (and she was also chained to the bell and stuff, but frees herself pretty easily). Incapable of catching the Temptress' car, she instead summons Pegasus.
It's pretty lucky that Furie wasn't injured in the crash, huh? That's the second time our heroes have endangered an innocent by deliberately provoking a car crash. Venus and Furie head to the summit atop Pegasus afterwards. Dr. Stellar, clearly regretting that he ever asked, tries to be like "Oh wow so it was the Great Minds Summit, that's great, see you later", but Venus passes the story on to Ultiman.
I was kind of bored of the formula, so it's good to see Ultiman changing it up -- he was already in Washington at the President's request, to serve as bodyguard to Winston Churchill. Churchill takes the time to see the Washington monument shortly before the summit is to begin. However, once he's inside, a steel door slides shut! Ultiman tears through it easily, but then the Washington Monument shoots out of the ground, because it's been turned into a rocket!
Ultiman finds the culprit, who is remote-controlling the rocket and plans to crash it into the White House to demoralize the Allied Forces. Naturally, Ultiman easily overcomes him and smashes his equipment, but this leaves the rocket unguided and it starts flying into space. Ultiman manages to save Churchill by grounding the monument in a really silly way.
Okay, so the conference is finally set to begin. All's well, right? As if. Nah; at the Smithsonian, the evil Henry Hyde reveals himself as the mastermind behind the whole thing. Born in the UK, Hyde was a brilliant scientist whose work was ignored due to his physical deformities. He moved to the USA, and was crushed when he wasn't invited to the Great Minds Summit. He swore he'd sabotage it and force the Allies to recognize his genius once and for all. And he still thinks he can, using his Anti-Matter Raygun to give life to the Smithsonian's exhibits!
Though "pandemonium results", Hyde's anger causes him to overload the gun, which blows up in his face, killing him. With the gun destroyed everything reverts to normal. One of the attending scientists realizes there's been some mistake -- he was mailed Hyde's invitation as well as his own, meaning Hyde did all this for nothing.
Despite this tragic development, the heroes are lauded by those in attendance, including Churchill, who compares them to the knights of his country's past. The seven of them band together as a force for good -- the Knights of Justice!