A young kid, Calvin Fuller (Thomas Ian Nicholas) is playing a baseball game when an earthquake opens up a rift in the ground and transports him to the 6th century, where he meets up with King Arthur. He also encounters the spirit of Merlin, who confirms that it was his magic which pulled Calvin back to Camelot. There are a lot of problems afoot, and Merlin will only send Calvin home if he puts things back to rights. Along the way, he falls in love with one of King Arthur's daughters, tosses off a lot of anachronisms, and ends up being transported back to his baseball game.
Has a rather obscure Direct to Video sequel entitled A Kid In Aladdin's Palace.
- Accidental Misnaming: Calvin accidentally calls Lord Belasco "Lord Elastic" at first.
- Actor Allusion: Merlin's actor, Ron Moody, previously played a more antagonistic Merlin in 1979's Unidentified Flying Oddball, also made by Disney.
- Adipose Rex: King Arthur has really let himself go in his old age.
- Anachronism Stew: Invoked; Calvin introduces several pieces of modern technology to the medieval world.
- And I'm the Queen of Sheba: Occurs while King Arthur and Calvin are traveling incognito to rescue Katy.Woman: And who do you think you are? The bloody King of England?
King Arthur: As a matter of fact, I am your King.
Woman: And I'm Cleo-bleedin'-patra!
- Arranged Marriage: Arthur is attempting to put together a marriage for his elder daughter Sarah, which distresses her because she already has a guy in mind. When the Black Knight reveals herself to be Sarah, Arthur gives his blessing to her choice.
- Bamboo Technology: Calvin ends up making "medieval" flavored versions of 1990s technology.
- Black Knight: A subversion; someone of this description initially appears like an antagonist but is actually a master jouster and gives to the people.
- Call-Back: At the start Calvin's coach tells him to remember three things but then lists four things instead. When Calvin starts training with Master Cain, he says the same thing.
- Chickification: Princess Katy has a sharp drop in physical competence in the final act and it leads to kidnapping from which she needs to be rescued.
- Contrived Coincidence: Luckily, right before the earthquake swallows him whole, Calvin grabs his backpack. Even more luckily, said backpack just happens to contain a number of items he will need on his adventure, like a flashlight and a Swiss army knife. Why would he bring those things to a baseball game? Also, he is told to get a bat for another boy, and when he grabs the bat, the one that would later be Excalibur, the earthquake begins.
- Death by Adaptation: In most traditional versions of Arthurian legend, Guinevere outlives Arthur and ends her days as a nun. Here, she died some time ago, leaving Arthur a widower with two daughters, Princesses Sarah and Katy.
- Devil in Plain Sight: Lord Belasco. When a character is first introduced as the king's trusted and loyal adviser, and the very first shot of the movie that he's in shows him as a tall dark man with black robes, a black horse, black hair with white streaks, a sinister smile, and ominous background music, it's just insulting to our intelligence. He's like Jafar, except he's not hypnotizing the king, so the king really has no freaking excuse for trusting him.
- Disneyfication: Of Mark Twain's original novel. The book was a satire and Genre Deconstruction of Arthurian lore that ended on a pretty depressing note, with the protagonist having all his achievements undone, then losing his friends, family and mind before finally dying. In this film, the entire plot thrown out in favor of a more conventional children's film with a hip, young protagonist, a Camelot that wouldn't be out of place in a theme park, and an unambiguously happy ending.
- Earn Your Happy Ending: Both Calvin and Princess Sarah. Calvin, of course, earns the right to go home. Sarah, by defeating Lord Belasco and winning the tournament for her hand in marriage, has - in her father's words - "won the right to choose," and of course opts to marry the man she loves.
- Evil Chancellor: Lord Belasco, who will stop at nothing to get the throne of Camelot.
- Falling Chandelier of Doom: Lampshaded and subverted: The title character cuts the rope attached to a chandelier, but it doesn't fall, causing him to comment that "this always works in the movies". How the chandelier isn't falling even though its support is cut is never explained.
- Faux Action Girl:
- Played straight with Princess Katy; In the training sequence is shown to be an excellent swordswoman, archer, and horsewoman; thus she should be able to take care of herself. Except, then she is kidnapped by some mooks, in broad daylight, and needs to be rescued by Calvin and King Arthur. A fight begins. Now on the good guys' side we have Arthur (a very old man), Calvin (a nerd who fails at baseball and has only trained in swordplay for a couple of days) and Katy (who is young, fast, and has trained in swordplay all her life). Arthur and Calvin fight and kill the mooks while Katy, who really should be "...able to take care of herself," is kidnapped again.
- The film also inverts the trope, with Katy's older sister Princess Sarah. The viewer spends the entire movie believing that tomboyish Katy is the tough one of the pair, only to find out that Sarah is the secret identity of the Black Knight, who has been fighting the enemy all along.
- First Kiss: Calvin gives Katy hers, a happy moment which is unfortunately followed immediately by her abduction.
- Girly Bruiser: Princess Sarah turns out to be this, since the Black Knight was actually her the whole time.
- Grail in the Garbage: Excalibur, which Princess Katy refers to as "just Father's old sword," has been left to molder in the filthy castle dungeon.
- Gratuitous Princess: Unlike in Arthurian myth, Arthur has two daughters who are major characters.
- Groin Attack: Calvin gets one in while fighting.
- Heroic BSoD: According to Princess Katy, Arthur suffered something like this after Guenivere died; she says that her father has never been the same since. This is why he's become a weak, doddering ruler, with Camelot in danger of falling under Lord Belasco's control.Katy: I miss my mother deeply, but I miss my father even more.
- I Have Your Wife: Katy is abducted on Lord Belasco's orders, so he can both make Arthur get rid of Calvin and force Sarah to agree to marry him. Of course, when Arthur and Calvin show up with the unharmed Katy, this doesn't work.
- Idiot Ball: Once Arthur learns Belasco schemes to usurp the throne; rather than have Belasco thrown in the dungeon, Arthur lets Belasco go free until the tournament. It is somewhat justified in that Belasco had become a major power in the kingdom whom many of the soldiers followed instead of the king. Throwing him in the dungeon was politically risky so he had to let Belasco disgrace himself.
- Intimate Hair Brushing: Older sister Sarah brushes younger sister Katy's hair before bed; it's their gossip time.
- The Lady's Favour: It is not a conventional example; Sarah and Calvin are initially the only ones who know that Katy has been kidnapped. Sarah urges him to go to Arthur and tell him what's happened and who is responsible, as she feels Arthur is Katy's only hope. She gives Calvin her handkerchief to give to her father, so that he will know Calvin was sent by her and is telling the truth.
- A Little Something We Call "Rock and Roll": Zigzagged. Played straight with Calvin's Discman. Then subverted later when he pulls it out again, only to use the lens inside to reflect light and blind a guard. What does he use when challenged to combat? "I choose... Combat Rock!" Cue guards holding their ears while Calvin rocks out.
- Loser Protagonist: Calvin starts the film this way; at the baseball game just before the earthquake, he is so intimidated by the flying fastballs that he doesn't even swing, and strikes out without moving a muscle. It's implied that this is not unusual for his character. Naturally, during his time in Camelot, he takes a level in badass and returns to his own time to lead his team to victory - with a baseball bat from the "Excalibur" brand, no less!
- Malingering Romance Ploy: Calvin is knocked from his horse during jousting training. He pretends to be more injured than he is so Princess Katy will fawn over him, and even manages to sneak in a kiss.
- Parental Marriage Veto: The subplot of the film is that Princess Sarah has refused to choose a suitor, so a tournament must be held to find a husband for her. She refuses to choose a suitor because the man she loves, Master Cain, is not of high enough rank to ask for her hand.
- Samus Is a Girl: Because of the Black Knight's full body armor and helmet, everyone assumes that a man is underneath it all.
- Self-Proclaimed Knight: The master jouster Black Knight is revealed to be Princess Sarah!
- Shop Class: Referenced when Calvin is instructing the local blacksmith on how to make something for him.Blacksmith: How does a boy know so much?
Calvin: Metal shop. Eighth grade.
- Spirit Advisor: Merlin appears only as a reflection in a well and only speaks to Calvin. It's not clear what happened to him or if he's dead; he's just said to have disappeared a long time ago.
- That Poor Cat: When Calvin fires an arrow through a window by accident, it hits a cat.
- Tomboy and Girly Girl: The two princesses; Katy is the tomboy who enjoys sword fighting and archery while Sarah is more interested in courtly things. In truth, Sarah has actually been riding around the country in black armor doing knightly things instead.
- Warrior Princess: Princess Sarah is the true identity of the Black Knight.
- Ye Goode Olde Days: The film had medieval England as a pretty nice place. It's moderately clean, and unless you stand under a window while walking down the street, you won't be covered in filth.note The Protagonist notes that his joust helmets smell something awful. Both the princesses are perfectly clean, but then again, they're princesses.
- Ye Olde Butcherede Englishe: Used inconsistently. Arthur frequently speaks this way, but almost no one else in his entire court does.