Season: 2
Original Airdate: December 15, 1967
Writer(s): Art Wallace
Director(s): Ralph Senensky
Guest Stars
Majel Barrett as Nurse Christine Chapel
Stephen Brooks as Ensign Garrovick
Jerry Ayres as Ensign Rizzo
Eddie Paskey as Lt. Leslie
William Blackburn as Lt. Hadley
Frank Da Vinci as Security Guard
Stardate: 3619.2
Synopsis: Kirk fights a cloud-entity from his past.