Big Barda BOOMS into the JLA Watchtower with a wounded Superboy who dropped at her feet. Barda, Wonder Woman, Steel and others start resuscitation.
Energy crackles from Superboy’s high-tech jacket. Zapped, Wonder Woman glimpses strange visions of alternate realities and heroes: Kamandi, the Tangent Joker, the ancient Superman, and more. Including alternate Challengers of the Unknown. Superboy gasps, “Blackness coming… This Earth next…” And dies. As Superboy walks in! Shocked, Superboy takes his alternate-corpse to Project Cadmus.
Doctor Rocket autopsies. The dead Superboy is identical to the local Superboy: closer than any clone. The jacket seems to incorporate New Gods technology too.
Superboy carries Mickey Cannon to the New Gods’ rolling fortress, the Mountain of Judgement. Their Gadget Guru determines the jacket is “like a life jacket – to bring a body back from a bad trip!” Except it’s not for dimension- or time-traveling. And the jacket’s DNA-specific: only Superboy can use it.
Superman and Batman theorize the jacket transcends Hypertime, which they learned of while battling Gog. The catch: to enter Hypertime, you need massive energy, like a nuclear explosion! Sweating, Superboy is strapped onto an atomic missile and shot into space. “Always wanted to go out with a bang…” he thumbs the trigger.
Awakening in the Batcave, he meets an alternate Batman – and a Superboy in Robin-like costume!