Operation: Annihilate!

     The episode starts out with the Enterprise's sensors picking up another ship heading perilously towards the sun. Kirk establishes a connection with a ship and tries multiple times to get them to reverse to no avail. As he's turning away he receives a distress call from the planet below, the same planet his brother Sam lives on. When the message stops Kirk exclaims that the voice sounded like it belonged to Sam's wife Aurelan so Kirk orders that they should go investigate the planet.
   On the planet Kirk and the landing party are charged by a group of men who shout warnings but wield bludgeoning objects. The crew uses the phasers to stun the crew then immediately run to a female's scream which happens to be Aurelan. When they find her she's screaming about some creature being here and trying to shut a grate.

Kirk tries to subdue her, but that doesn't seem to work so Bones gives her a sedative to relax her. As Kirk tries to tell her everything's okay, Bones finds two other bodies: the comatose body of Kirk's nephew Peter and the deceased body of his brother Sam(who is funnily enough also played by William Shatner, the only other Star Trek character other than Captain Kirk he ever plays.)

 

     Bones insists on bringing everyone back on board for examination. Once on board and examinations have proceeded McCoy tells Kirk that it is lucky that Peter is comatose because if conscious he would be in severe pain. Aurelan on the other hand is awake and not taking well to the medicine McCoy is giving her. Kirk tries to question her for information, but all he learns is that the creatures spaceship crashed it was using people to help rebuild the ship. 

    Kirk and the landing party go back down to the planet to search for the creatures and follow an odd buzzing noise to an area filled with odd amoebe like creatures. They shoot one down with the phasers set to kill, but it barely damages it. As the crew is turning to leave it attacks Spock. Kirk removes it quickly but it seems its too late. Spock is hurt. 

    Back on the Enterprise McCoy examines Spock and finds long tentacles wrapped around Spock's nervous system. These same things are found in the system of Peter and Aurelan. As McCoy is telling this to Kirk, Spock leaves the sick bay and makes his way to the front of the ship where he tries to take control of the ship. Several people including Kirk try to subdue him, but it is very obvious Spock is much stronger than them. It isn't until  Bones uses a sedative on him that he stops.

        Back at the sick bay Spock has shackles now but he insists he's fine and that he control the pain. He wants to hep Kirk but Kirk denies him and tells him to stay in bed. This doesn't sit well with Spock and soon he's escaping again, this time heading towards Scotty, a security officer, and the landing pods. Spock tries to convince them to let him down, but Scotty won't let him. Spock and Scotty have a bit of a show off which ends in Scotty pointing a phaser at Spock to keep him contained. Scotty calls for help and soon Kirk, McCoy and a few more security officers have entered the room. Scotty explains his side of the story and Spock does the same to which Kirk replies by letting Spock go down to the planet, through Bones's protests. 

      On the planet Spock is able to capture one of the amoebe creatures and bring it back to the ship. Kirk orders all the medical and life science technicians to examine the creature. After examining for a while everyone is stumped. Nothing will kill it. Nothing except the sun. Kirk, Spock, and McCoy try to figure things out but come out short trying to figure out what properties of the sun will kill the creature. Until it hits them: LIGHT!! 

     McCoy sets up a test and throws all forms of light at the creature, which dies. HURRAY! but Kirk isn't sure it will work on those with pieces of the creature in their nerves on the planet. McCoy alters the test so it has planet conditions then tests it on a willing volunteer: Spock. Bones warns Kirk and Spock that this could have serious consequences to the optic nerve, but Spock insists. McCoy pulls the lever and when the test is over Spock says he feels much better...but then admits to being blind. The nurse comes in moments later with test results that say he only needed to use UV rays which would not have blinded Spock.

    They send UV rays over the planets surface which kills off all the creatures, which turned out to be brain cells of a much bigger creature. 

      After everything is fine and dandy Kirk tries to explain to a guilty McCoy that Spock's blindness is not his fault, but it isn't until Spock walks onto the bridge of the Enterprise with sight intact that they both feel better.
   The episode then ends with quips between Bones and Spock, and the realization that Vulcans have an extra pair of thin invisible eyelids that instinctively kicked in which is why his sight came back.