Plot

The Enterprise encounters a gigantic energy draining space organism that threatens the galaxy.

The Enterprise is sent to investigate the disruption of the Gamma VII-A solar system and the destruction of the U.S.S. Intrepid, staffed solely by Vulcans. When they arrive they find a large dark mass floating in space that is draining energy from everything around it, including the Enterprise. Drawn into the mass, they find a huge amoeba-like creature and Kirk must decide which of his two friends, McCoy or Spock, to send into it aboard a shuttle craft on a mission of no return.—garykmcd

Kirk has always considered McCoy a dear friend. And Spock as well. What would he do if he were faced with the choice of sending one of them to almost certain death in a necessary sacrifice that both of them are eager to make. Namely, their life.

The Enterprise is on its way to Starbase 6 for a period of R&R. It encounters a mammoth single-celled organism which is draining power out of the universe, and is growing. The Intrepid, a Federation star-ship, manned entirely by Vulcans has just been destroyed. Spock felt a huge burst of mental energy as it was destroyed. He sensed the death of all of the Vulcan crew. Kirk asks him "what did you sense?" Spock answers "Astonishment." Starbase 6 asks the Enterprise to investigate the GAMMA 7A system, which is now suddenly dead.. it has a sun and billions of inhabitants.

As Enterprise proceeds towards GAMMA 7A, it finds a dark blob in its path. The blob is not solid, liquid or gaseous, nor is it any kind of energy that the Enterprise has encountered before. Soon the blob engulfs the Enterprise and people on the ship start falling ill with alarming frequency. In addition, the ship's energy reserves are started to drain.. McCoy says that the crew is simply dying. The Enterprise is being pulled further towards the center of the blob, and the engine are acting in reverse. All Scott can do is to apply thrust to keep the enterprise from plunging towards the blob. Scott says that the engine have power for 2 more hrs.

Kirk sends a probe and finds that the blob is a large single celled organism, and performs all the basic functions of life. it drains energy from other life forms to survive. The Amoeba does not have a purpose, it is simply a living thing which drains energy out of everything in its path. Spock soon discovers that it is going to reproduce. They might be able to destroy it but they need more information, especially as to the location of its reproductive cells.

In order to find this information out, they need a manned probe. The unmanned ones have been destroyed. Which means a volunteer. McCoy is the biology expert, but Spock is the Science officer. Kirk has a tough choice. He brings them together. "I'm sorry, Mr Spock" he says. McCoy smiles. "I'll get my things ready." "No, Bones, you don't understand. I'm sorry, Mr Spock, but you are the most qualified to go."

As Spock is taking readings, his radio reports are full of static, but he is also transmitting them electronically. At one point, the organism lurches and Spock is tossed about the interior of his small pod. When he returns to the radio he says "Doctor, you would not have survived it." Spock sends all the information and Kirk figures out that an antibody might help destroy the organism. Kirk order Scott to divert all power to the shields and allows the Enterprise to be sucked into the organism's body. Kirk fires a antimatter bomb (the organism works in reverse, and is not impacted by matter, so must be impacted by anti-matter) which has a timer into the amoeba's reproductive cells, which should destroy it entirely.

As they are preparing to warp out, the sensors pick up Mr Spock's pod, which they had thought was lost. Spock says "save the ship." But McCoy says "Shut up, Spock, we're saving you." Spock comments dryly "Thank you, CAPTAIN McCoy." They are able to pull Spock out safely, the Enterprise is safe, and the creature is destroyed.

As Spock is taking readings, his radio reports are full of static, but he is also transmitting them electronically. At one point, the organism lurches and Spock is tossed about the interior of his small pod. When he returns to the radio he says "Doctor, you would not have survived it."

Spock sends all the information and Kirk fires the bomb which has a timer into the amoeba's reproductive cells, which should destroy it entirely.

As they are preparing to warp out, the sensors pick up Mr Spock's pod, which they had thought was lost. Spock says "save the ship." But McCoy says "Shut up, Spock, we're saving you." Spock comments dryly "Thank you, CAPTAIN McCoy." They are able to pull Spock out safely, the Enterprise is safe, and the creature is destroyed. Wow. All is resolved.