Captain Kirk must learn the limits to the power of a 17-year-old boy with the psychic ability to create anything and destroy anyone.
The space vessel Antares rescues Charles Evans from the forbidding surface of the planet Thasus, and then hurriedly hands him off to the Enterprise. Soon, mysterious happenings dog the boy, who cannot seem to learn certain vital lessons of adulthood. Finally the humiliated teen reveals prodigious psionic powers that could even threaten the survival of the Federation. Who is Charlie, really, and where did he get these abilities?
Charlie Evans is a teenage boy who has been raised by aliens since infancy. He knows little about humankind so when he comes aboard the Enterprise, he is now in a truly alien environment. He has few social skills and while he is very intelligent, he has the emotional maturity of a toddler and is quick to anger when he does not get his way. He also has great power and can change matter into any form. He takes an interest in Yeoman Rand without realizing the biological drives that are at work. Fed up with being told what he can and cannot do, he decides challenge Kirk's authority directly.
- Charlie is a teenager, and has teenage desires and needs, but there is a big twist.
Charlie is not only a teenager. He has tremendous powers, granted to him by the Thasians, who gave him these powers to save his life when he was left stranded, the only survivor of a crash, and he was a baby, alone, on their planet.
While the Thasians were not looking, an earth ship, the Antares, found Charlie and took him aboard, until a larger starship, the Enterprise could transport Charlie to where there are many other people, male and female, for Charlie to live with.
But Charlie has powers, and he has a temper. He is angry at the Captain of the Antares for getting rid of him, so he mentally removes an important part of the Antares' warp engine with his mind, and their ship explodes in space as they are speeding away.
Now comes the real trouble. Charlie is sensitive, and also he likes women when he sees them, ESPECIALLY Yeoman Janice Rand, the pretty personal yeoman to Captain Kirk, who wears her hair tied up, and wears a uniform with black leggings and boots. Charlie, at first, does some harmless tricks with his power to impress her, but soon he is doing bad things.
Yeoman Rand tries to introduce him to a female crew member who is Charlie's age, but Charlie is stubborn, and wants Yeoman Rand or nobody.
He loses his temper, and soon he is using his mind to make crewpeople vanish and he makes the teenage girl lose her face. Yeoman Rand fears for her safety.
Kirk tries to discipline Charlie, but the boy is out of control! What can Kirk do?
But wait!! The Thasians, who are close to gods, appear in space as a big face, to take Charlie back.
Kirk tries to reason with them. "Perhaps he can be taught not to use his powers."
But the Thasians are very strict, and say...
"We gave him his powers to survive, but with his teenager's mind, he would use them to destroy you and all of your worlds."
Charlie pleads with everyone. Then he is gone, vanished, taken, back to the desolate planet.
Yeoman Rand is sorry and cries. But Kirk realizes it had to be. He comforts Janice, and all is resolved.