In a room on Vulcan designed to provide distracting stimuli, Spock engages in a contest of logic with another young Vulcan, Salak, who defeats him with a series of taunting arguments about his half-human ancestry. McCoy appears in the room, which is actually inside Spock's mind. The Enterprise is battling two Klingon battle cruisers, which are driven off but are expected to return. Spock and McCoy find themselves in a hedge maze which is Spock's mental garden of logic. Spock was captured by the Klingons and subjected to their mind-ripper; he has been rescued but remains unconscious. The mind-ripper was also taken from the Klingons, and McCoy is hooked up to it in Sickbay, using it to enter Spock's mind. The hedges turn brown and attack Spock and McCoy. Kirk also enters Spock's mind and bla