Superman; Lori Lemaris (guest star); Superboy (flashback); Lex Luthor (flashback); Nathan Hale; Abraham Lincoln; John Wilkes Booth; Jor-El; Lara; Zor-El; Lyla Lerrol; Alura; Chief Sitting Bull
Synopsis
Lori Lemaris asks Superman to go into the past and stop Atlantis from sinking. Superman, who has never successfully changed the past tries and is amazed that it succeeds. Superman continues to change other past events, including the assassination of Lincoln, Custer's Last Stand and the explosion of Krypton.