Green Lantern [Hal Jordan]; Martian Manhunter; Wonder Woman; Green Arrow [Oliver Queen]; The Flash [Barry Allen]; Batman; Superman; Aquaman; Snapper Carr (cameo) (all as the Justice League of America/JLA); Speedy (cameo); Pieface (cameo); Jimmy Olsen (cameo); Sforll; Zed Brann (villain, flashback); Ragnar (flashback)
Sforll transports the Justice League to his lair to enlist them in preventing Zed Brann from stealing the life force ("vita-matter") of our universe for his own. They must fight robot duplicates of themselves to save the universe.
Superman; Batman; Green Lantern [Hal Jordan]; The Flash [Barry Allen]; Wonder Woman; Aquaman; Green Arrow [Oliver Queen]; Martian Manhunter [John Jones/J'onn J'onzz]; The Atom [Ray Palmer]; Snapper Carr (all as the Justice League of America/JLA); Midge (Snapper's girlfriend); The Protectors of Starzl (androids named Terrane, Ocana, and Etheran)
The JLA is brought to a sub-atomic world where they need to defeat the protectors of that world in order to save its people.