On a planet resembling 1960s Earth, all of the adults have perished from a deadly disease.
1-28: The City on the Edge of Forever
After following a delusional McCoy into 1930s Earth, Kirk must make a heart-wrenching choice to save the future.
1-07: What Are Little Girls Made Of?
The Enterprise finds Nurse Chapel's long-lost fiance, Dr. Roger Korby, living isolated with advanced androids.
1-06: Mudd’s Women
The Enterprise rescues known criminal Harry Mudd and his mysterious female companions.