"Free LSD for everyone!"
The Enterprise accidentally breaks into an alternate universe, one in which magic is real, and are immediately greeted as old friends by a satyr-like figure named "Lucien" who brings them down to his planet to show them the wonders of magic on his planet, Megas-Tu.
Then, some Puritans show up to put them on trial for past misdeeds and reveal that the jolly "Lucien" has another name that's more familiar to them.
This episode provides examples of:
- Asmodeus: The chief prosecutor of the Salem Witch Trials is revealed to be Asmodeus, who remembers how his people were vilified by greedy and guileful Earthlings. He appears in human form wearing the pilgrim-like garb appropriate for the setting.
- Beethoven Was an Alien Spy: The Megans traveled to Earth and taught medieval human's genuine magic. They left after the people of Salem wigged out and started murdering them.
- Failed a Spot Check: Asmodeus notices Spock is nonhuman and different to the others, but pays no attention to the Cat Folk Lieutenant M'Ress and the three armed Lieutenant Arex.
- Fate Worse than Death: Lucien is sentenced to be alone in a separate universe for the rest of time. Kirk protests that this is as good as a death sentence.
- Heart Is an Awesome Power: Spock deduces that belief shapes reality in this universe, therefore, the existence of magic is quite logical. He soon demonstrates it himself, and implores Kirk to "believe" during the showdown with Asmodeus.
- Humans Are the Real Monsters: Asmodeus calls humans the most vile, treacherous species in the universe.
- Humanity on Trial: The whole crew is put in pillories by Asmodeus, who still has bad memories over what happened in Salem.
- Louis Cypher: "Lucien" isn't trying very hard to hide his true identity. It's just that Kirk isn't as up on his Abrahamanic lore as viewers are.
- Love Potion: Lucien points out a lady purchasing one of these. Since you can look as young and beautiful as you want, apparently these are the new necessity for getting a man.
- Paper-Thin Disguise: A horned satyr whose name means "Light" offering apples to the crew.
- Trickster Archetype: Lucien is mischievous and constantly laughs over Kirk's bafflement with the magic universe, but he's genuinely fond of humans.
- Satan: It's pretty clear from the start who "Lucien" really is. Especially when he hands a couple of apples to the crew on his tour of the magic universe.
- Satan Is Good: This doesn't come with God Is Evil like it usually does, but Lucien really isn't a bad guy here. In fact, he's a lot nicer and more open-minded than the other people in his universe, who take a lot of convincing to believe that humans are okay now.
- Secret Test of Character: Asmodeus' cruel sentence on Lucien proves to be a test to see if humanity has truly changed. Kirk's willingness to fight for Lucien proves that they have, and Asmodeus declares that they're welcome to visit at will.
- Where the Magic Went: According to this episode, all the magical beings told of in Earth's legends came from Megas-Tu in the first place (except, presumably, for all the other Ancient-Astronauts-worshipped-as-gods that have turned up on Star Trek), and retreated back there when the witch hunts started up.
- Wizard Duel: Kirk takes on Asmodeus in a battle of magic to save Lucien from eternal isolation in a bubble universe. He's hopelessly outclassed, but fortunately Asmodeus is just testing him.
