Season: 3

Original Airdate: January 3, 1969
Writer(s): Teleplay: Lee Erwin
Story: Lee Erwin and Jerry Sohl
Director(s): Herb Wallerstein
Guest Stars
Keye Luke as Governor Donald Cory
Steve Ihnat as Fleet Captain Garth
Yvonne Craig as Marta
Gary Downey as Tellarite
Richard Geary as Andorian
Frank da Vinci as Lt. Brent
William Blackburn as Lt. Hadley
Roger Holloway as Lt. Lemli
Stardate: 5718.3

Synopsis: An insane shape-shifter becomes Kirk’s duplicate.