Guest Stars James Doohan as Lt. Cmdr. Montgomery "Scotty" Scott Nichelle Nichols as Lt. Nyota Uhura Walter Koenig as Ensign Pavel Chekov Majel Barrett Roddenberry as Nurse Christine Chapel Booker Bradshaw as Dr. M'Benga Nancy Kovack as Nona Ned Romero as Krell Paul Baxley as Patrol Leader Michael Witney as Tyree Janos Prohaska as The Gumato Arthur Bernard as Apella Gary Carpenter as Yutan