Kirk and the derelict starship Defiant vanish into a spatial interphase between universes. To rescue him, Spock must maintain position despite a growing, violent hysteria aboard the Enterprise, like that which destroyed the Defiant's crew, as well as a force field being laid around the Enterprise by Tholian patrol ships. Written by
Did You Know?
is the credited director of this episode. Ralph Senensky
was the original director, but was fired midway through filming, and replaced by Wallerstein. Senensky refused any screen credit for this episode. See more
While transporting Kirk back onto the Enterprise there is a close-up of the transporter operator's hands. His rank has changed and he is missing a finger on the right hand - clearly those are Scotty's hands and rank. See more
Even Scotty's being affected. If Scotty goes under, that's the finish of whatever chance we have of getting the Enterprise out of here.