Mirror Universe Enterprise Crew [James T. Kirk (death); Mister Spock; Marlena Moreau; Doctor Leonard McCoy; Nyota Uhura; Hikaru Sulu; Montgomery Scott; Pavel Chekov; Ensign Fein; Lieutenant Idelson]; Admiral Decker; Lord Skarl; Krimm; Enterprise Crew [James T. Kirk; Doctor Leonard McCoy; Nyota Uhura] (flashback)
In the Mirror Universe, the ruthless Mister Spock arrests Captain Kirk for failure to obey an order, even though he knows Kirk was temporarily transported to a parallel universe and replaced by his counterpart. Marlena betrays Kirk by giving Spock the secret of the destructive Tantalus Field, which Spock uses to obliterate a Klingon fleet. Kirk, Sulu, and Uhura work to overthrow Spock, but the Vulcan triumphs and kills Kirk, permanently winning the command for himself.
dilithium crystals; Emterprise; Klingons; Mirror Universe; parallel universe; Tantalus Field