Action Prologue: Subverted in the first episode, which begins in the middle of an intense swordfight that is revealed to be a friendly play between siblings.
Advertised Extra: Sheena Easton as Queen Anne. She has spot in the opening credits despite appearing for about a minute each in two of the first five episodes — and her appearance in "The Exile" is just to explain that she's gone on vacation and a Suspiciously Similar Substitute will take her place. She gets a larger role in "Secrets of the Father," "Four Musketeers and a Baby" and "The Girl from Upper Gaborski," but still doesn't appear at all in 6 out of 13 of the episodes.
All Girls Want Bad Boys: The highwayman in "Four Musketeers and a Baby" builds his image around this, targeting coaches with women in them, flirting, and giving them scarves as keepsakes. It reaches the point where women write ballads about him and ride around in a carriage trying to get robbed. It's implied that he gets pardoned in the end in part because Queen Anne herself falls into this mindset.
Seeing this trope in action prompts Louis to dress as the highwayman in order to become more attractive to women.
All Just a Dream: The ending of "The Invincible Sword", although there's some ambiguity there.
All There in the Manual: The official website's bio of Siroc identified him as a former slave, but this piece of information never appeared up in the show.
Sheena Easton also gets a "with" credit in later episodes.
Arranged Marriage: Between Louis and Tatiana in "The Girl from Upper Gaborski." Louis seems okay with it, although mostly just glad to have someone around who has to listen to him, while Tatiana complains for the whole episode. Leads to a very funny scene where Queen Anne and Cardinal Mazarin give her marital advice:
Anne: A state marriage is like a state dinner: you might not like the menu, but it's impolite to show it.
Mazarin: If you would, think of Louis as... asparagus.
Anne: Eat your vegetables in public, dear, but have your dessert in private.
"The" D'Artagnan: I ordered you confined to the garrison... and you disobeyed my orders yet again, knowing it would assure your expulsion from the Musketeers... and (beat) you saved my life.
D'Artagnan: Well, nobody's perfect.
Artistic License – Geology: the plot twist of "The Girl from Upper Gaborski" rests on the idea that quartzite can be mistaken for diamonds. Even if they meant quartz, it's a stretch.
As You Know: D'Artagnan explaining the backstory to Jacqueline in the second episode.
Handled less clumsily in other episodes, but they all include a short dialogue where D'Artagnan points out that Jacqueline is a woman, in case the audience couldn't tell.
Author Powers: In the series finale, Jacqueline and D'Artagnan meet Alexandre Dumas as he's writing their story. He answers questions about their characterization, puts dialogue into their mouths, and says that because he created them, they will die if they kill him.
Badass Decay: Pointed out in-universe when D'Artagnan discovers that his famous Musketeer father has been reduced to performing for money and selling action figures of himself.
Bang Bang BANG: Averted in "Four Musketeers and a Baby," when the Highwayman warns D'Artagnan that firing a gun next to a baby will injure the baby's eardrums.
Black Comedy Rape: In the series finale, Siroc invents a love potion that makes women want to have sex with him. He and Ramon try it out, and it backfires when the women try to chase them down and have sex with them some more after the men are too tired to continue. All Played for Laughs.
Blasting It out of Their Hands: Jacqueline does this in "The Exile," D'Artagnan in "Secrets of the Father." Both times, the guy holding the gun is completely uninjured.
Blatant Lies: When Jacqueline loses her shirt, Gerard justifies throwing her a new one with "he's ashamed of his belly button."
Break The Fake: Siroc examines what he believes to be a fake diamond, then smashes it into powder to prove that it is fake, because a real diamond wouldn't be so easy to destroy. (Much to the chagrin of the other Musketeers, who helped pay for what was sold as a real diamond, and planned to return it to the pawn shop after Siroc was done studying it.)
Call Back: In "The Exile," when Jacqueline says that killing the guard who killed her father is not murder, Charles replies, "No; it's satisfaction." In "Secrets," when Jacqueline kills Bernard after he kills her brother, his last words are, "You have your satisfaction."
Calling Your Attack: D'Artagnan could have gotten a sneak attack in before throwing off his disguise in "To Heir is Human", but he alerts his opponents instead.
Camp Straight: King Louis XIV. (It would be Ambiguously Gay except that he shows clear interest in women beginning about halfway through the series). Of course the ridiculously flamboyant costumes/make up/huge blonde wigs etc are par for the course for a 17th century French King, but Robert Sheehan really, really camps it up, to the point where it couldn't possibly be unintentional.
May be a case of Informed Ability. Over the course of the series, he loses most of his love interests to his companions, and the one mention of his abilities as a lover comes from a woman driven to become a nun after experiencing his poor performance.
Censor Suds: Jacqueline's bath in "The Invincible Sword."
Character Focus: Several episodes give characters other than D'Artagnan and Jacqueline a chance in the limelight: "Enchanted" for Ramon, "Da Vinci's Notebook" for Siroc, "The Girl from Upper Gaborski" for Louis, and "The Chameleon" for Duval.
Chekhov's Gun: Ramon's stinky cheese in "Rub-a-Dub Sub," which everyone complains about, saves the day twice at the end of the episode.
Clarke's Third Law: When questioned by Andre about science in "Enchanted," Siroc suggests that "maybe magic's just another word for what we don't understand."
Clingy Jealous Girl: Mireille in "Da Vinci's Notebook," who pines over D'Artagnan (and then "Jacques").
Disguised in Drag: Siroc in "The Invincible Sword." Including a pregnant belly made from a watermelon that's actually a bomb.
Disproportionate Retribution: In the first episode, Louis threatens to have Mazarin executed for being mildly annoying. (He changes his mind when Mazarin reminds him of how many boring and tedious things he'd have to do himself if Mazarin weren't around.)
Dreadful Musician: King Louis spends the majority of "Da Vinci's Notebook" playing various musical instruments very ineptly. He eventually settles on the drum because there aren't any "bad notes" on it. He still manages to play it very badly, though.
Everybody Laughs Ending: "Four Musketeers and a Baby," after the Musketeers find out that a woman D'Artagnan had been trying to track down because he thought she was the mother of his baby had become a nun after he passed out "like a useless turnip" before they could do the deed.
Gadgeteer Genius: Siroc's bizarre and improbable contraptions quite often save the day. His inventions include a flying machine, a submarine, a machine gun, a metal detector, and a watermelon bomb. Often Played for Laughs; for example:
Siroc: (Seeing D'Artagnan get thrown across a table and faceplant into a woman's cleavage) Bags of air could save lives!
(Later in the episode, while complaining about cleaning the dungeon and declaring that he'll work on a miracle cleanser:)
Siroc: What if it were a lotion and a cleanser?
Ramon: A lotion and a cleanser in one?
Siroc: A man can dream, can't he?
Probably the funniest example is his static electricity machine, which involves artificial feet covered in socks and attached to a conveyor belt, which he turns with a crank so the socks rub against a static-generating material. A huge step up from running in socks on a fake treadmill (which he does earlier in the season).
Gasshole: Ramon pretends to be one in order to cover for a hidden baby.
Girls with Moustaches: Jacqueline wears a fake mustache and beard to infiltrate a gang in the episode "Rub-a-Dub Sub." Halfway through the series, she permanently augments her male disguise with a fake goatee.
G-Rated Drug: Characters are occasionally shown getting extremely high on coffee.
It even gets banned, with the royal doctor suggesting that people "indulge in some harmless stimulant like tobacco" instead.
Gross-Up Close-Up: Oliver Cromwell's fabled mole. So hideous it virtually gives the King a panic attack and causes him to be haunted by some very surreal nightmares.
A Handful for an Eye: During Jacqueline and D'Artagnan's duel in the first episode, she ends up underneath a cow at one point, and proceeds to spray milk in his eye straight from the udder. This, coupled with a timely Groin Attack, enabled her to win the duel and secure her identity as a Combat Pragmatist.
Historical In-Joke: A quote attributed to the historical Louis XIV is, "I am the State." In fact, he said the opposite: "I depart, but the State shall always remain." In "The Girl from Upper Gaborski," Louis utters a similar quote — "I am the mighty state of France!" — while flexing shirtless in the mirror and fantasizing about how to impress women. Putting the quote in the mouth of a 15-year-old Spoiled Brat/Cloudcuckoolander — someone who's just discovered women and the fact that he has royal power — explains how the same person could say both quotes.
I Always Wanted to Say That: Jacqueline on the classic Musketeer motto ("All for one and one for all!"), when D'Artagnan shuts her down.
Quoted exactly by Louis in the Dream Sequence extended ending of "The Invincible Sword."
I Am Not My Father: D'Artagnan struggles to get out from under his father's shadow as a legendary swordsman and is determined not to make his father's mistakes, like abandoning his family. But he does throw "like father, like son" in D'Artagnan, Sr.'s face after being accused of not lying well.
He even leaves the Musketeers in order to raise his child because his father prioritized the Musketeers over him.
Ignore The Disability: After having nightmares about Cromwell's ugly wart in "The Exile," Louis accidentally greets him with, "Welcome to France, Monsieur Cromwart!" When Mazarin gives him a dirty look, he doesn't seem to realize he said anything wrong.
Ramon: D'Artagnan met these sisters. They're triplets. It's gonna be a wild night.
D'Artagnan: And if you two find ladies of your own, you're welcome to join us.
The Immodest Orgasm: Ramon thinks this is happening in "The Girl from Upper Gaborski," when in reality it's Louis getting kidnapped.
Improvised Weapon: In her first duel with D'Artagnan, Jacqueline trips over some melons, then impales one on her sword and flings it at him. Later, she falls next to a conveniently placed cow and squirts him in the eyes with its milk.
Louis knocks out an attacker with a metal tray in "The Girl From Upper Gaborski."
Louis: Who's your king now?
Incredibly Lame Pun: In "Enchanted," when D'Artagnan announces that Ramon's new love is a poetess, Louis asks if she "has good lines," making an hourglass shape in the air. He continues to ask if everyone gets it as they all look awkward or roll their eyes.
Insane Troll Logic: In "The Chameleon," Louis reads part of a book from India saying that the Master of Changing Light, after years of intense study and training, can make himself look like other people. He tries concentrating for a few seconds and then gives up. Leads to this scene later in the episode:
D'Artagnan: What if I told you there is an impostor in Paris who can look like anyone?...
Louis: You've been reading that book of fairy tales, haven't you? The Master of Changing Light?... Pure fantastical nonsense! I mean, I tried it myself, and if the King of France can't bend his appearance to the force of his will, I ask you, who can?
Large Ham: Charles Shaughnessy looks like he's having a world of fun hamming it up as "The" D'Artagnan. Completely justified, as the character himself is a large ham.
Last Name Basis: Even D'Artagnan's father calls him D'Artagnan. Although his first name is never given, some fans have speculated he's named after his father, Charles de Batz de Castelmore, Comte d'Artagnan.
Love at First Sight: After Jacqueline rescues Charles II in "The Exile," he spends only a few hours with her before offering to make her his queen.
The Main Characters Do Everything: Every important investigation goes to the four main characters. Even though there are clearly Musketeer extras, on more than one occasion, Duval goes through the garrison shouting "Musketeers!" when he's actually looking specifically for the four main characters.
Louis: Just turn a blind eye; there's a good man... And a blind ear, for good measure.
Mood-Swinger: King Louis, although in a relatively benign and ineffectual way. While he is often charming and pleasant, he is sometimes whiny, petulant and volatile and has tantrums over nothing. Mostly justified in that he is meant to be a teenager.
Mood Whiplash: The ending of "The Invincible Sword." In a nutshell: the darkest, angstiest episode in the series is all a dream, and the villain they fought in the beginning is actually an escaped mental patient who is rescued by a tiny nun. Even the characters think it's Mood Whiplash, judging from Jacqueline and Louis' expressions in particular.
Must Have Caffeine: Queen Anne in "To Heir is Human," when her doctor tells her to stop drinking coffee, followed by the Musketeers when coffee is outright banned.
Leads to Siroc inventing a coffee brewer using compressed steam in a desperate attempt to re-use old grounds.
Narrator: In the uncut versions, most of the episodes end with Ramon delivering a poetic summary (and sometimes an Aesop), apparently acting as an omniscient narrator.
No Name Given: Captain Duval only goes by his last name until the second to last episode, "The Chameleon," when his ex-fiancee calls him by his first name.
Not Even Bothering with the Accent: Bearing in mind that the regular cast, all of whom are supposed to be playing Eurpoean characters, generally don't bother to modify their (mostly Canadian and American) accents, it's particularly hilarious when someone actually does take a random stab at authenticity only to sound bizarre, jarring and often incredibly hammy.
Interestingly, the very Irish Robert Sheehan fakes an Americanadian accent as Louis, while Sheena Easton fakes an English accent. You'd think they'd have her do an American accent, as she was born in Scotland but seems to have lost most of her original accent after moving to the U.S., and it would have kept the main cast consistent.
Obfuscating Disability: A spy for Mazarin pretends to be a deaf man begging for money in order to get close to the Musketeers without suspicion.
Omnidisciplinary Scientist: Siroc is knowledgeable in biology, engineering, forensics, medicine, and whatever other branch of science the plot requires.
Only One Name: Siroc; it's unclear whether this is a first or last name.
Ooh, Me Accent's Slipping: For the most part, Robert Sheehan does a very good American accent for Louis, but you can hear his Irish accent come through on a few words. Most noticeable at the end of "The Girl from Upper Gaborski," where he seems to forget he's supposed to be faking an accent at all for an entire line.
Our Zombies Are Different: Type R(evenant), in "Coat of Arms." An ancient knight rises from the dead with a single drive: find his stolen artifact no matter what the cost.
Paper-Thin Disguise: Jacqueline is an utterly convincing man to the other characters, despite the fact that at first she hardly bothers to disguise herself at all. (In the second half of the series, the obviously fake goatee only makes things worse.)
Inverted in "The Chameleon," where D'Artagnan says he was suspicious of the Chameleon disguised as Jacques because he was "too masculine."
Lampshaded somewhat in the first episode: Captain Duval reassures Jacqueline that although the other men might make fun of her high voice, that doesn't mean she won't make a good soldier.
There are actually quite a few brilliantly shoddy disguises over the course of the series. In "Secrets of the Father," the Duke, who has been wooing Queen Anne, later accosts her while wearing a mask that only covers a portion of his face. And he doesn't disguise his voice at all, but she still doesn't recognise him.
Sort of averted in "Four Musketeers and a Baby" when Louis dresses up as a highwayman as part of a scheme to get girls to like him, but is recognised instantly despite his disguise being arguably better than any other featured on the show — at least he looked radically different without his wig, which is more than can be said for any of the others.
Parental Abandonment: D'Artagnan has some majordaddy issues, stemming from the fact that his famous musketeer father was never there for him, even when his mother passed away. He is shown coming to terms with this, however, and he and his father do reconcile somewhat in "Secrets of the Father."
Poirot Speak: Ramon occasionally throws random Spanish words into his dialogue.
Pre-Mortem One-Liner: Jacqueline gets to spout one of these in the prologue after Mazarin's guards kill her father:
Jacqueline: You sent a good man to Heaven — now you go to Hell!
Profiling: When a Spaniard attempts to assassinate Louis in "The Invincible Sword," all Spaniards are rounded up and investigated, including the badly injured Ramon. Used to show Jacqueline's transformation into a villain.
And then Mazarin comes under suspicion not because of any of the things he's done so far in the series, but because "how different is an Italian from a Spaniard?" Possibly justified, as Jacqueline was trying to convince King Louis.
Protagonist-Centered Morality: In "To Heir is Human," Jacqueline convinces Celeste not to kill Captain Bernard in revenge for her husband's death because he can be tried and executed. But then it turns out that he can't be, and they just let him go. Two episodes later, she tells Gerard not to kill Bernard, because If You Kill Him, You Will Be Just Like Him. But when Bernard kills Gerard, she immediately kills him in revenge.
Not to mention her getting angry at Charles for wanting to avenge his own father's death by killing Cromwell. (Although partly justified, as she's concerned that Cromwell's death would be bad for France.)
Running Gag: D'Artagnan's love interests falling in love with "Jacques."
Ruritania: Upper Gaborski, a fictional nation whose residents have bad Slavic accents.
Sequel Hook: Gerard's discovery of a secret about Jacqueline's past in the final episode seems to set up a story arc for the (nonexistent) next season.
Series Continuity Error: When Jacqueline meets The Great D'Artagnan in "Secrets of the Father," she excitedly goes on about how she used to swordfight with her brother while pretending to be The Great D'Artagnan. D'Artagnan (the younger) clearly hears this and doesn't seem to be surprised or care. In "Secrets," Jacqueline is suddenly very embarrassed about pretending to be The Great D'Artagnan and doesn't want D'Artagnan to know about it. When he overhears, he teases her about it. Neither of them seem to recall him finding out about it before.
Smart Ball: Louis, despite being about sixteen years old and every inch the Upper-Class Twit, can apparently translate the arcane Indian text he is presented with in "The Chameleon," simply because the plot required an Infodump.
Siroc: If you're the real Captain Duval, tell us something only he would know.
Duval: Like what?
D'Artagnan: Like what we got you for your last birthday.
Duval: Nothing. Bunch of thoughtless, shiftless recruits.
Siroc: Yeah, that's the Captain.
Spell My Name with a "The": Characters differentiate D'Artagnan (the main character) from his famous father by referring to the latter as "The D'Artagnan." Leads to D'Artagnan clarifying, in the first episode, that he's "the son of the the."
Tin-Can Telephone: A variation: Siroc invents a tin can telephone-like device using metal cups and some string, which he uses to eavesdrop on the Cardinal's Guards.
Title Drop: In Ramon's poem at the end of "Wanted":
"And now for country, and for king, and for the good of all things ride the Young Blades."
Tone Shift / Early Installment Weirdness: Although there are still funny moments, the comedy and silliness is played down and the drama and fantasy are played up beginning in the third episode ("Enchanted").
Trailers Always Spoil: Charles II's identity isn't technically revealed until about halfway through the episode, but since it was shown in the trailer, it doesn't seem to cross anyone's mind as an actual spoiler.
Verb This!: Gerard's response to "Kneel and kiss the dust [Mazarin] might deign to tread" is "Kiss this." Leads to him getting arrested and his father getting murdered in a stunning display of Disproportionate Retribution.
Writers Cannot Do Math: In the first episode, Louis is stated to be 15 years old, as Mazarin refers to him being crowned "next year, when you’re 16." However, the date given at the beginning of "Da Vinci's Notebook" is 1652. Since Louis XIV was born on September 5, 1638, he would be either 13 or 14 in 1652.
You Killed My Father: In the opening of the very first episode, Cardinal Mazarin orders Jacqueline's father killed; she kills the henchman in revenge, and spends the rest of the series disguised as a man in order to avoid capture and hopefully get revenge against Mazarin.
In addition, the last episode features Jacqueline's brother being killed by Mazarin's new henchman; she promptly kills him, too. Amusingly, they're both played by the same actor.