Executive Producer: Gene Roddenberry
Producers: Gene L. Coon + John Meredyth Lucas
Associate Producer: Robert H. Justman
Script Consultant: D. C. Fontana

Story by: Jerome Bixby
Writers: D. C. Fontana and Jerome Bixby
Dir.: Marc Daniels

Captain Kirk: William Shatner
Science Officer, First Officer, Cmdr. Spock: Leonard Nimoy
Dr. Leonard "Bones" Mc Coy: DeForest Kelly
Lt. Sulu: George Takei
Lieutenant Commander Montgomery Scott: James Doohan
Lieutenant Uhura: Nichelle Nichols
Nurse Christine Chapel: Majel Barrett
Rojan: Warren Stevens
Tomar: Robert Fortier
Kelinda: Barbara Bouchet
Lt. Shea: Carl Byrd
Yeoman Leslie Tompson: Julie Cobb

Stardate 4657.5

The Enterprise is answering a distress call. Having reached the planet, the landing party tries to find the source. Yeoman Tompson's and Spock's tricorders detect two lifeforms and two humanoids approach. One of them simply informs the crew that they are going to take over the ship. By a subtle touch to a device at their belt, Rojan and Kelinda, the two humanoid people paralyze the crew. All motionless they listen to Rojan explaining to them that resistance is useless. The neutralizer neutralizes nerve impulses. They have come from the Andromeda Galaxy, from planet Kelva, and assumed the human body to adjust for traveling conditions.

As the effect is stopped, Rojan goes on telling the now moving landing party that they are taking the ship in order to occupy the galaxy. "I am sorry," Kirk says, "this galaxy is already occupied." But he listens to their story: On their way to find a galaxy suitable to occupy, their ship, designed for multi–generation–usage, was destroyed. All barely escaped in a craft. Kirk mentions "colonize" and is answered: "We don't colonize, we conquer – the fate of the inferior. ... Ceased in these shells ... how do humans manage to exist in these shells?" Before leaving for the ship they lock the landing party in a cave. Thinking of a way to escape, Kirk suggests the Vulcan to reach the guard outside with his mind, through the scale, to suggest that they have escaped - a trick he already used on Eminiar VII.

One of the four Kelvans, Kelinda, stands outside the cave and guards the blocked entrance. She is reached by Spock's mind, but hers proves to be stronger. Spock is pushed off the wall he made contact through. Kelinda comes in to investigate. Kirk knocks her unconscious and takes the device, which caused them to be immobilized, from her belt. Outside, they are stopped and Kirk is paralyzed again. Rojan takes the device out of his motionless hand. The Kelvan states that this cannot be left unpunished. Under the eyes of Kirk, Spock and McCoy, both Lieutenant Shea and Yeoman Leslie Thompson, are transformed into small, edged, tetrahedral, gray blocks. Rojan takes one and crushes it. The other is restored: Lt. Shea. Leslie Tompson cannot be restored- her fragments are a heap of sand.

They try to analyze what the Kelvins really are. Spock shares that he was thrown back by the vision of immense beings. All ideas seem to be of little effect and they chose to go back on board of the Enterprise. Spock is ordered to be sick. He concentrates and falls down. McCoy demands that he and his comrade are immediately sent back to the Enterprise, where he will be able to treat Spock. The trick works and they are beamed on board. Meanwhile Kelinda becomes interested in flowers. Kirk, still remembering Leslie Tompson, answers har questions, but is not really in the mood for explaining names of flowers.

On board, all the personnel has been reduced to tetrahedral, gray blocks to save food resources. Only Kirk, Spock, McCoy and Scotty are left as they are, to maneuver the ship. Spock and Scott have prepared for self- destruction of the Enterprise. Kirk agrees – in case there is no other choice to prevent the Kelvans to conquer the galaxy. Both are waiting for the captain's signal, but Kirk does not give it. Talking about the Kelvans later, Spock mentions their superior senses. To keep them intact they spare on senses like taste, feelings ... They have taken human form - by this redeveloping senses. Kirk: "Let's make use of that!"

Scott takes on one of the Kelvins and introduces him to alcohol. He sacrifices his best and precious bottles, even an alien one he does not know himself. As the Kelvan asks what kind of alcohol this is, all Scotty knows is. "It's green." After a long time the Kelvan sleeps and Scotty manages to get his device from his belt ... but he himself only makes it to the door. Kirk kisses Kelinda, with the excuse that he wants to apologize. She wonders what this is for and he says it's because he has knocked her down. Thinking that this approach was useless, Kirk just wants to try something else, as she asks him to apologizes again. Rojan comes in and does not like what he sees, but Kelinda insists of her own life. Dr. McCoy injects the fourth Kelvan because he looks sick, and injects him again because the human body needs it – not telling him that the injections make him sick.

Spock plays chess with Rojan and does not waste any time triggering Rojan's jealousy towards captain Kirk. He also mentions that a kiss is a sign of affection. When Rojan bursts into the room Kirk and Kelinda are in and finds them kissing - his envy rages. He begins to fight with Kirk. Kirk shouts at him: "You are human. Your reactions are human! What happened in the short time you were exposed to us? What will happen in some hundred years?" Rojan realizes he has changed and they will be aliens in their own world. As Kirk proposes that they could settle here and begin a new life, Rojan asks: "Would you welcome invaders?" "No, but we welcome friends." They agree and wonder where they could start and McCoy suggests the planet they have been on.

Head picture courtesy of Ultimate Pix