"Museum at the End of Time"
After regaining control of the ship, Spock is unable to get any readings. According to the sensors, the ship is "nowhere". An old man with white hair appears on the view screen and tells Kirk not to fear. He says the ship is in safe hands, and asks Kirk to follow his "receiving beam". Kirk refuses, but the ship is pulled through the void anyway by a mysterious force. The Enterprise arrives at a huge island floating in space. A large building dominates the island, and space ships of every kind are scattered about on it.
Kirk beams down to the surface with Spock and Dr. McCoy. The old man meets them on the surface, and identifies himself as the "Curator". He introduces a large blue dog-like creature with him as his bodyguard, Hilliard. The Curator tells the landing party that he and his museum were not always on the island. Once they lived on Krugar III. The planet was destroyed by a huge comet which laid waste to the planet, snatched up a small section of land surrounding the museum, and hurled it through the universe at incredible speeds. The museum and it's island fell into a "hole in the stars" to arrive at it's present location.
The Curator leads the landing party through the twisting corridors of the museum until they reach a large lounge filled with all kinds of creatures. The curator tells them that they are the beings who manned the spaceships lying around the museum. Kirk introduces himself to several humans in the group, and asks the Curator where exactly they are. The Curator tells Kirk that the they are in "limbo" - a place between places, a time without time.
When the Enterprise entered the "netherspace" it ceased to be in the real world. Kirk vows to find a way to escape. The other creatures tell Kirk that they have all tried - to no avail. Spock theorizes that that the museum could explain the legends of famous "lost ships" that the cultures of many worlds have. The Curator tells the captain that they are not prisoners, and that they have the run of the museum, and anything else that they require.
At that moment, a large group of Klingons arrive and threaten to kill Kirk. The creature Hilliard bravely attempts to save Kirk by attacking the Klingons, and is killed by disruptor fire. The landing party uses this distraction to charge the Klingons (who are all bald, and wearing green skin-tight outfits, and super-hero type boots), however they are knocked unconscious and held captive in the museum along with the Curator, and all of his other guests. Kirk asks the Klingon commander why he is holding them captive. The Klingon tells him that it is Klingon nature to control everything that exists, and that "this abysmal chunk of dirt" will be Klingon property when they leave.
Hilliard shows up - weak but still alive. He chews through the landing party's bonds, freeing them. They attack the Klingons, and regain one of their communicators. Kirk calls the Enterprise, and Scotty beams the landing party back to the ship just before the Klingons fire disruptors at them. Scotty then beams the other guests of the museum, along with the Curator up to the Enterprise, leaving the Klingons behind.
The guests agree to help fight the Klingons, and beam back to the surface armed with phasers. The battle destroys many of the museum's exhibits. Spock holds the Klingon commander at phaser point and he agrees to a truce. Spock explains that the "limbo" is dying, and that within hours the netherworld will reach the "end of its universal cycle" - with an explosion that will shatter worlds. He tells them that the dimensional gate can be opened if a sufficient amount of force is applied to it.
The Klingons agree to add the firepower of their ship to that of the Enterprise. Both ships open fire on the nothingness until a patch of real space appears.
Kirk asks the Curator to come aboard with all his guests, but the Curator tells him that they are all happier in the museum, and would be oddities in the the real world. He bids them farewell. The Enterprise and the Klingon battle cruiser leave the nothingness, and return to real space. Just as they exit - a blinding white flash signals the close of the gateway to the netherworld.
Kirk and the Klingon commander agree that it would be foolish to work together one moment and then destroy each other the next, however the Klingon tells Kirk that they will meet again. The Enterprise sets course for Starbase 9 for minor repairs.