Story continued from previous issue.
Lex Luthor and Mr. Mxyzptlk are the 30th century descendants of the 20th century villains of the same name. Both heroes are inducted into the Legion at the end of this story. This Mxyzptlk is also the brother of Mask Man (Mxyzptlk V), the villain who tried to wipe out the Legion in Adventure Comics #310 (the editor's note incorrectly says #130).