The Moor is home to three peoples. Normal people live in the Mounds, and farm and hunt. The Dorig live in the lakes and rivers, and are tricksy and magical. (The Dorig regard themselves as normal people, and refer to the people of the Mounds as "Lymen".) Giants live on the far reaches of the Moor, and no sensible person has anything to do with them.
Gest, the chief of the Mound called Garholt, is a Hero. He wed the daughter of the chief of Otmound after a fairy-tale courtship (three impossible tasks, Giants, Dorig, and all) and two of their three children possess magical Gifts. The third, Gair, is a puzzle and a disappointment — but it's Gair who will be the key to undoing a Curse affecting all the people of the Moor, which began long ago with a meeting between the sons of a Lyman chief and a Dorig king.
Tropes featured include:
- Ambiguously Human: Each of the three races in the story is this from the point of view of the other two. At one point, the Giant children try to resolve an argument between themselves and the Lymen over which of them are 'real people' by suggesting that 'they can be people, and we can be humans', but they soon get used to thinking of their Lymen and Dorig friends as human. The implication is that they are all different subspecies of human.
- …And That Little Girl Was Me: At one point, a story is told about two young men named Jerry and George. It's immediately obvious to all present who they are, but he's telling it that way to make a point.
- Beware the Nice Ones:
- When Gair gets mad he throws three bullies out a window.
- When Ceri gets mad he freezes his antagonists with his mind.
- The Call Put Me on Hold: Gair is the only one of his siblings who doesn't have a Gift. He turns out to have, unrecognised, the rarest — and possibly the most painful — Gift of all, Sight Unasked.
- Don't Make Me Take My Belt Off!: Used as a punishment among the Lymen. At one point Gest is pressured into punishing Gair for something he'd rather not, and resolves the situation by taking Gair into the next room and taking the belt to an inoffensive piece of furniture for the benefit of the people listening.
- Emo Teen: Both Gair and Gerald seem to to be made of this.
- Engagement Challenge: When Gest asked Chief Og of Otmound for his daughter's hand in marriage, Og set him three impossible tasks as a way of turning him down diplomatically. Gest completed all three tasks anyway.
- The Fair Folk: The Dorig, from the point of view of the Lymen.
- Fish out of Water: The Lymen Children in the Giants' house.
- Functional Magic: both Rule Magic, in the case of the 'words' which the main characters use, and Inherent Gift.
- Notably, none of the three races regard their own abilities as magical. From the point of view of the Lymen, being able to change reality by speaking is no more magical than saying 'Pass the bread, please,' and real magic is things like the bizarre artifacts that Giants craft - which from the Giants' point of view are just technology.
- Hostage Situation: Toward the end, one of the characters volunteers to be taken hostage to provide a pretext for negotiations to be opened between the conflicting races. It doesn't go so well.
- Human Sacrifice: Well, not humans per se, or it depends on how you define human, but the Dorig sacrifice each other.
- I Know Your True Name: A major threat to the Dorig and Lymen is to simply mention that one has the name of an enemy in mind, as having a person's name allows you to curse them. Ceri scoffs at the Giants for giving out their names so freely.
- Humans Are Cthulhu: Played with and averted. Giants, who refer to themselves as 'humans', are regarded as dangerous monsters by other races - but ultimately, humans are people, like everyone else.
- King Incognito:
- Lyman chiefs look just like everyone else, due to the fact that they all wear camo to blend in with the grass.
- Hafny and Halla turn out to be a Prince and Princess. Surprise!
- Literal Genie: The Gift of Asked Sight enables its possessor to instantly give an accurate answer to any question about the future — but she can only answer the question she's asked, even if it's worded badly, overly narrow, or based on a false assumption. Ayna spends a lot of time worrying about what might happen because of this.
- Little People: All the characters who aren't Giants; it turns out that the "Giants" are humans.
- Older Than They Look: The Lymen children, when compared with the Giant children.
- but paradoxically, also the Giant children. The Lymen, seeing so-called 'Giants' who are only slightly bigger than themselves, wonder whether these are baby Giants. But when they look more closely, they realise that these are adolescents around their own age. It turns out that Giants aren't that much bigger than Dorig and Lymem.
- Rule of Three: All over the place, as you'd expect from the title. There are three Powers, three races, three tasks, three siblings, ...
- Shrouded in Myth: Gest's three tasks. Eventually, it's revealed that Gest is a Fake Ultimate Hero but still cool.
- Tomato Surprise: The 'giants' are really humans, and the protagonists are 'little people'.
- Voluntary Shapeshifting: The Dorig have this ability.
