Superboy-Prime is stranded at Earth-0 when he’s sent back to the main DC timeline after his battle with the Supermen and the collapse of the multiversal conflict; the best match in the source material is around the end of Infinite Crisis and the follow-up events, not a single clearly labeled “chapter.”

Where it happens

  • After Infinite Crisis , he ends up in Green Lantern custody, which leads into later stories.
  • The sequence that leaves him effectively “stranded” or displaced from his original Earth continues through Countdown and Legion of Three Worlds.
  • Some summaries also describe him as being trapped in the Speed Force before returning to the main Earth later.

Plain-language answer

If you mean the exact comic issue or chapter, it is not usually given as one single chapter in summaries. The closest answer is the end of Infinite Crisis / aftermath leading into later crossover issues.

Best reading order

  1. Infinite Crisis.
  2. 52 / Countdown.
  3. Final Crisis: Legion of 3 Worlds.

TL;DR

Superboy-Prime becomes displaced from his home reality and ends up on the main Earth during the Infinite Crisis aftermath , with the story continuing across later crossover issues rather than one named chapter.