Captain Kirk is caught between dimensions while the crew of the Enterprise works to retrieve him. All the while, the Tholians demand that the Enterprise leave their space.

Captain Kirk faces off with a demented shape-shifting starship captain determined to control the universe.

The Enterprise encounters two duo-chromatic and mutually belligerent aliens who put the ship in the middle of their old conflict.

Kirk, McCoy, and Sulu are stranded on a barren planet where a mysterious woman attempts to kill them one at a time, while the Enterprise must travel halfway across the galaxy to rescue them.

The Enterprise is in danger when Janice Lester, one of Kirk's former lovers, steals his body.