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.
1-29: Operation: Annihilate!
A planet, home to Kirk's brother and nephew, is under attack by unique creatures.
1-26: Errand of Mercy
Kirk and Spock try to protect a seemingly primitive species from a Klingon invasion.
1-27: The Alternative Factor
Enterprise encounters Lazarus, whose behavior is representative of two drastically different personalities.