Episode 17 Charlie's Law Broadcast April 29th 1967
On mission date 643.6, the Endeavour takes charge of Charlie Brown (guest star Dennis Waterman), a teenage boy from a small Klingon cargo vessel called the Prakciss. As a three-year-old child, he was the sole survivor of a transport ship that crashed on the planet Fazus on the edges of Klingon space. For 14 years Charlie grew up, stranded in the wreckage, and apparently only learned how to talk from the ship's computer systems that somehow remained intact.
The boy is to be transported to his nearest living relatives on Wessex, a Commonwealth world settled by Humans, and the crew of the Prakciss speak nothing but praises about Charlie. They seem, however, more than pleased to see the boy removed from their ship as soon as possible and after the transfer (during which Charlie gives an ominous glare), they bid the Endeavour an unusually hasty goodbye and depart. This is put down to them being Klingons and not really knowing how to deal with a human teenager. Charlie undergoes a cursory medical examination by Dr. M’Beke and Charlie tells the doctor that the crew of the Prakciss did not like him very much, and that all he wants is for people to like him.
Charlie quickly becomes obnoxious, and shows signs that he possesses strange powers. First, he develops an infatuation with Yeoman Amy Johnson (Gabrielle Drake), who is evidently the first human female he has ever seen and also comes from Wessex like his relatives. He presents her with a bottle of perfume, which turns out to be her favorite scent, even though there is none of it in the ship's stores. Having observed a man in engineering seal an agreement to go to the recreation room with a friendly slap on the rear, he does the same to Johnson, to which she of course objects.
Charlie meets Johnson and Rand later in a recreation room, where Spock (whom Charlie later calls "Mr. Ears") plays a Vulcanian Lyre, and Lt. D’Alembert sings. Charlie is annoyed with being a subject in D’Alembert's performance as well as Johnson paying more attention to the song than to him, so he causes D’Alembert to abruptly (but temporarily) lose her voice.
As the Endeavour reaches the jump point, it receives a message from the Prakciss, but the message gets cut off before it can be finished. Charlie makes the curious and sinister comment, "It wasn't very well constructed." But shortly after, Spock determines that the Prakciss has blown up. Progressively more bizarre events begin to take place aboard the Endeavour. For example, a cook reports that the synthetic meatloaf in the kitchen has been transformed into real sheep.
Back in the recreation room, Decker defeats Holmes at chess, beating Holmes' mastery of the game with his own quirky move. Charlie is intrigued with the game and tries to duplicate the same feat but loses quickly. Decker and Holmes leave the room, but an angered Charlie stays behind and causes the white chess pieces to melt, revealing he has both a bad temper and powerful telekinetic abilities.
Later, Decker tries his best to interest Charlie with something other than following Johnson everywhere, and attempts to teach the young man how to play Squash. Decker's training partner Crewman Cook (Robert Arnold), laughs at Charlie’s attempts, and Charlie makes him "go away"; Cook vanishes before Decker's eyes. Shocked by what he has witnessed, Decker calls for security guards to escort young Charlie to his quarters, but Charlie says he will not let them hurt him; he then makes their phasers disappear. Charlie admits he used his powers to destroy the Prakciss, but says the ship would have blown up on its own sooner or later, and regardless, he insists, "They weren't nice to me."
Charlie takes control of the Endeavour. He forces Braun to recite Earth poetry, turns Rand into a cat, and chases down Johnson. When she resists his advances he gets angry and makes her disappear, saying, "She wasn't nice at all." Charlie tells everyone that he can make him or her all go away, anytime he wants to. Decker and Spock attempt to confine him in a detention cell, but to no avail. Charlie goes on a rampage, insisting “Be nice to Charlie, OR ELSE!” transforming or vanishing members of the crew who mock him or rebuff him.
Decker has resigned himself to setting the self destruct and laments that this is beginning to get to be a habit, finding people with great mental powers and trying to destroy the ship to stop them. Two glowing spheres appears on the bridge, saying that their race gave Charlie his powers to help him to survive on their world, but these powers render him too powerful and therefore dangerous to live on Wessex. The spheres are sorrowful over the loss of the Prakciss (which they could not save), but return Yeoman Johnson and repair the damage Charlie has done. They apologize to Decker and promise to take Charlie to live with them. Charlie begs Decker for forgiveness and pleads frantically with him to not let the aliens take him away. Decker does ask if the spheres could take Charlie’s powers away so that he could live amongst humans but they refuse saying that he now couldn’t live without them, as they have become an integral part of him. So Decker lets the spheres take Charlie away.
