'The Corbomite Maneuver' by Jerry Sohl (a.k.a. Nathan Butler)

While exploring an uncharted region of space, the Enterprise encounters a cuboid space buoy warning ships away. When the alien object repeatedly blocks their path, Captain Kirk orders its destruction; however, as soon as the buoy is blown up a gigantic, crystalline sphere appears and traps the Enterprise. A strange alien contacts them, identifying itself as Balok, of the vessel I.S.S. Fesarius. It states that Kirk and his crew have trespassed and committed hostile actions, and must therefore be destroyed. Hopelessly outmatched, Kirk is forced to attempt a desperate bluff; he informs Balok that if the Enterprise is attacked, the corbomite in its hull will self-destruct, thereby destroying both vessels. Unless Balok believes Kirk's claims, the captain and his ship face imminent destruction - or do they..?

William Shatner (Captain James Tiberius Kirk), Leonard Nimoy (First Officer Lieutenant Commander Spock), DeForest Kelley (Doctor Leonard H. ‘Bones’ McCoy), James Doohan (Chief Engineer Montgomery ‘Scotty’ Scott), Nichelle Nichols (Lieutenant Nyota Uhura), George Takei (Lieutenant Hikaru Sulu), Clint Howard (Balok), Anthony Hall (Lieutenant Dave Bailey), Clint Howard (Balok), Vic Perrin (Voice of Balok), Ted Cassidy (Voice of Balok Puppet)

Directed by Joseph Sargent

TX:
10th November, 1966

Notes:
*Featuring Captain James Tiberius Kirk, First Officer Lieutenant Commander Spock, Doctor Leonard H. ‘Bones’ McCoy, Chief Engineer Montgomery Scott, Lieutenant Nyota Uhura and Lieutenant Hikaru Sulu