Word comes to the city of Tenabra that a Dark army is amassing in the west, the likes of which has not been seen since the Sorcerous Overlord Shanhih was defeated, centuries ago. Count Ruane of Tenabra leads a force of knights and armsmen to aid in the realm's defence, among whom are Ser Silvus de Castro, a knight from a disgraced noble family, possessed of a small magical talent and an inquisitive mind, and his squire, Will Parkin, who get to see up close the perils of the Dark and what can become of He Who Fights Monsters.
Their troubles are not over when they return home, for the Prince of the Riverland is looking to expand his domain, and has taken an interest in the possibilities of magic as a tool for conquest. He wants to add Silvus to his tool chest, and he's not going to take "no" for an answer...
This series provides examples of:
- Accidental Proposal: In A Dark Journey, Arienne's hometown has a custom involving the prospective groom proposing by offering the lady a pair of shoes, which Will only finds out about after he's unknowingly invoked it. Fortunately, this is a case where he would have got around to proposing sooner or later anyway and both parties are perfectly happy with the outcome.
- Addictive Magic: A recurring theme is that the use of magic, and especially of Dark magic, can be addictive. In A Dark Journey, a mage dips into the Dark for the first time in her life in a moment of desperation, and says afterward that now that she's felt it once she will spend the rest of her life having to guard against the temptation to try it again.
- Animal Eye Spy: In A Dark Journey, a magic user repeatedly taps into the senses of birds and other animals to track fugitives or get a high-up overview of the situation. She mentions at one point that she avoids bats, because she finds their echolocation too difficult to interpret.
- Burn the Witch!: In A Dark Victory, Asta is threatened with being denounced as a necromancer and burned at the stake if she doesn't use her magic to assist Prince Nathan (by doing exactly the kinds of things that would get her burned at the stake if people found out). When she does ultimately defy Prince Nathan, he proceeds to carry out the threat, though she's rescued from the stake at the last moment.
- Church Militant: The Order of the Lady of Victories is an army of paladins founded to guard against the rise of a new Sorcerous Overlord.
- A Dog Named "Dog": In A Dark Winter, Will mentions in passing that his landlord's guard dog is uncreatively named "Dog".
- The Empire: The Big Bad of the trilogy is Prince Nathan, ruler of an expansionist nation that's already hoovered up all the little independent fiefdoms in the Riverland and is looking to add still more territory. He isn't an Evil Overlord, just a regular historically-plausible conquest-hungry dictator; in the long run, much more dangerous.
- Emotion Control: When a Dark mage uses mind control on a victim, the main component is manipulating the victim's emotions so that they want to do what the mage intends them to do.
- Evil Overlord: Deconstructed. The author started writing it to explore questions like "Just what does the Evil Overlord get out of lurking in Mordor and trying to take over the world?" and "Where does he get the Always Chaotic Evil cannon fodder from?"
- Forced Food Taster: In A Dark Journey, part of Arienne's plan to free Will and Silvus involves coming to keep their guards company with a flask of drugged wine. One of the brighter guards is suspicious enough to make her drink a cup of the wine first, but she passes the test by using magic to neutralise the drug — and incidentally the intoxicating effect of the alcohol — in her own cup.
- Gondor Calls for Aid: The inciting incident of A Dark Winter is Ys sending out a call for aid against the new Dark army. In the case of Tenabra, they have a promise from a former Count that when the day comes, his descendant will send three lances of knights, but due to the county's reduced circumstances Count Ruane is only able to offer six knights with their squires and a squad of men-at-arms. After various casualties and desertions along the way, what Ys actually gets from Tenabra is two knights, two squires, and a suspiciously well-armed cook. Which fortunately turns out to be a lot better than nothing.
- Good Cop/Bad Cop: Mentioned in A Dark Journey, where Will remarks to Silvus that the way Prince Nathan's two underlings are trying different approaches to persuade them to co-operate reminds him of the "hard man, nice man" routine they used to do when they were both in the city watch — with the difference that, when they did it, you could tell which one was meant to be the nice man.
- Half-Human Hybrid: Will encounters a few people with mixed goblin-human ancestry.
- Henchmen Race: Deconstructed. Goblins are thought to be an Always Chaotic Evil henchman race, because the only time they've interacted significantly with humans was as the Evil Overlord's mooks; it turns out that they're actually a peaceful and artistic people when left to themselves, but as a species they have a low resistance against telepathic domination that makes them really handy to anyone with mind control powers and a sudden desire to field an army.
- I Will Only Slow You Down: During the escape from Sarcastle in A Dark Journey, Will is slowed down by his injuries and tries to insist that the others go on without him. Silvus refuses to leave him, and fortunately they find a safe hiding place soon afterward.
- Karmic Death: In A Dark Victory, Prince Nathan's flunky who was appointed to keep Asta in line and repeatedly threatened to have her burned at the stake, burns to death after being caught in a highly flammable booby trap while trying to recapture her.
- Language of Magic: Discussed in A Dark Victory; an expert on magic says that there's a folk belief that words in ancient tongues can be magical, but there's no truth in it: magic is controlled entirely by the will of a person with the talent, words or no words.
- Last-Second Word Swap: In A Dark Journey, Will starts to say "Taking the risk, my arse", but in deference to a lady's presence switches at the last moment to "my auntie".
- Left-Justified Fantasy Map: There's a map, bordered with an ocean on the west, but the usual associations are inverted — instead of having the Evil Overlord in the east, the heroes living in the west, and an Avalon-equivalent over the ocean, the heroes live in the east and the Evil Overlord's heartland is over the ocean to the west.
- Lodged-Blade Recycling: In the climactic fight between Will and Barras in A Dark Journey, Barras throws a dagger at Will, which lodges in his sword-arm and forces him to drop his sword. In the ensuing tussle, Will pulls the dagger out of his arm and stabs Barras with it. The narration makes a point of mentioning how much it hurts and how much of a desperation move it is.
- Lovely Assistant: When Will first meets Arienne in A Dark Journey, she's acting as the assistant to a stage magician called the Great Wandini. As part of the act she wears a skimpy outfit that she later explains to Will is intended to keep the audience's attention on her and off Wandini (and Will admits with embarrassment that it certainly worked on him).
- Magicians Are Wizards: The Great Wandini in A Dark Journey is mostly just a prestidigitator, but his most impressive trick is done with real magic. This gets him into hot water when Prince Nathan decides to start collecting pet magic users. (The real problem, it turns out, is that Wandini has no magical ability at all — it's his Lovely Assistant who makes the Rabbit Trick work.)
- Magic Is Evil: A lot of people believe this. The Sorcerous Overlord probably had something to do with it, but it's also pointed out in A Dark Journey that magic is by definition unnatural: magic causes things to happen that go against the laws of nature, that's how you know it's magic.
- Make It Look Like an Accident: In A Dark Journey, Barras tries to murder Will without getting in trouble for it by challenging him to a demonstration match using practice swords with blunt wooden knobs on the ends, and then 'accidentally' knocking off the knob of his sword to reveal the sharp point and trying to run Will through quickly enough that he can pretend he hadn't noticed it was gone.
- Medieval European Fantasy: Written by somebody who's studied actual medieval history, not just read a lot of earlier Medieval European Fantasy.
- No-Holds-Barred Contest: The duel at the end of A Dark Journey is invoked according to an old custom that means that there are almost no rules about what the combatants can't do to each other. Silvus spends an entire paragraph listing possibilities that aren't barred, including kicking, clawing, gouging, biting, throwing sand in an opponent's eyes, and stabbing an opponent somewhere non-lethal and then backing off until he bleeds to death. He misses "wait until your opponent thinks you're done for, and then get him with the hidden back-up dagger he didn't know you had", which is the trick that almost wins the fight for Barras.
- No Name Given: In A Dark Winter, the doctor in charge of the infirmary at Waycastle. In A Dark Journey, Will ends up in the same infirmary again, and lampshades the fact that he still hasn't learned her name.
- Not Listening to Me, Are You?: In A Dark Journey, Will gets distracted while Arienne is telling him her life story, and when he starts paying attention again, she's testing him by asserting that she ran away from home after her father ate her baby brother for lunch.
- Our Goblins Are Different: When they're not being enslaved by the Sorcerous Overlord, the underfolk are a peaceful and artistic race (with elements of the Standard Fantasy versions of elves and dwarves) — but good luck getting people to believe that, particularly since they're still definitely ugly by human standards.
- Our Monsters Are Different: A variety of fantastic creatures appear or are mentioned, including goblins, dragons, wyverns, trolls, unicorns, and some kind of horrible giant armoured bug that everybody's too busy fighting to name. Goblins are the only ones that are a naturally-occurring species; all the others are created individually by Dark mages using magic to mutate a mundane animal or person.
- Powerless Performer, Extraordinary Assistant: Grames, aka The Great Wandini, is a traveling stage magician who secretly makes use of real magic in some of his tricks. Prince Nathan learns of this and has Grames and his Lovely Assistant Arienne imprisoned so that Grames will use his magic to the prince's benefit. What Prince Nathan doesn't know - and Grames and Arienne are both very keen that he doesn't find out - is that it's Arienne, not Grames, who has the talent for real magic.
- Predecessor Villain: The Evil Overlord Shanhih, who was defeated in a costly battle a few centuries earlier. Over the course of the trilogy, several people attempt to set themselves up as his successor, for various reasons of their own.
- Puberty Superpower: It's established in A Dark Victory that the magical gift comes into its full strength when a person reaches puberty.
- Puppet State: In A Dark Winter, Tenabra is a puppet state of The Empire, which swept through and gobbled up all the nations in the Riverlands a generation ago; most of them were completely absorbed, but because the Count of Tenabra chose not to fight back, he was rewarded by being allowed to nominally retain his rule, although stripped of the power to make any real decisions without the nod from his new overlord. One of the characters snarks that the biggest decision the current Count ever has to make is which outfit he's going to wear to a state ball. A significant plot point concerns the revelation of how far another character is prepared to go to regain Tenabran self-determination. In the sequels, Count Ruane's failed attempt to throw off the yoke has been used as a justification to disinherit his family and absorb Tenabra as another directly-ruled province.
- Secret Test of Character: In A Dark Journey, Silvus, Will, and Arienne meet with a group of goblin Elders, who are understandably wary about humans, and especially humans with magical gifts, and fake a threat to test their reactions. Arienne, who has the most experience with goblins, is the first to realise it's a test, and worries that Silvus has failed it, but it turns out that the Elders are testing for several different things and there's more than one way to pass.
- Sorcerous Overlord: The Evil Overlord is of this type.
- Switching P.O.V.: The narration of A Dark Victory alternates between Will, the narrator of the first two books, and Asta, the new mage who has been pressed into Prince Nathan's service.
- Telepathy: It's revealed in A Dark Journey that the underfolk largely communicate among themselves by telepathy rather than speech. They can also communicate the same way with humans who have some magical ability; the downside is that this is part of why they're so vulnerable to being mind-controlled by mages who have gone Dark.
- Two-Part Trilogy: Winter was originally written as a standalone novel. Journey and Victory were plotted together after the publisher started thinking in trilogies, and form two parts of a single story.
- Wedding Finale: A Dark Victory ends with the wedding of Will and Arienne.
- What Happened to the Mouse?: In A Dark Victory, it's never revealed what became of Asta's unicorn after she's separated from it.
- You Didn't Ask: In A Dark Victory, when Asta finds out that Arienne is also a mage, she asks why Arienne hadn't told her before, and Arienne says, "It never came up." Asta immediately calls this out as an evasion, which it is; Arienne went out of her way to avoid mentioning it when she first introduced herself, because at the time, and for most of the time since, it would have made Asta view her as a threat and an enemy.