What’s the deal with dragons? Mythical creatures abound, but dragons seem to be the Rorschach blots of contemporary fantasy, embodying – with their scales, hoarded treasure, and breath of fire – all our anxieties and obsessions. In Vancouver writer Rachel Hartman’s debut young adult novel, we meet shape-shifting dragons that can almost pass for human, though in that form they have no real understanding of emotion and don’t get the point of art. They also seem a bit like stereotypical grad students with bad beards and no fashion sense.

The setting is reminiscent of Renaissance Europe, and Hartman does an impressive job walking the line between familiar and strange: alongside the dragons, slash-sleeved courtiers wander the streets, and the sound of shawms and sackbuts float out over the town. Society is kept in line through hierarchies of royal court and church.

There are three official species – humans, dragons in human form, and an underclass of smaller dragons. A treaty between humans and dragons, in place for 40 years, is now up for renewal. All is not well, however: a prince has been murdered and a rogue dragon is suspected.

Enter our reluctant hero, Seraphina, a young assistant to the court composer, whose shocking secret is that her mother was a dragon and her father a human. Mating between the two types of beings is not supposed to be possible, and Seraphina feels unique and grotesque – her mixed origins give her a special sensitivity to both species, as well as some tell-tale physical markers. As the plot thickens with a deftly constructed espionage storyline and an equally fresh and convincing love story, Seraphina finds herself burdened with maintaining the fragile peace of the kingdom while simultaneously striving to keep her lineage a secret.

This kind of plot, full of the mechanics that keep an “other” world ticking along, is what true fantasy lovers adore. Readers who respond to a phrase such as “a saarantras might discern that it was quigutl-made” will eat up all 400-plus pages. Dragon-­fanciers who wonder how the creatures actually breathe fire will be delighted by this answer, from a character who is an expert on dracomachia (the art of dragon fighting): “Dragons are flammable.… They developed their flame for use against each other.… Their hide is tough but it burns, given enough heat for enough time; their insides are volatile, which is how they flame in the first place.”

What distinguishes the book from standard dragon fare, however, is the language. Music is essential to Seraphina’s identity; it is her link to her dead mother, her work, and her point of access to the court. Hartman matches this theme in the musicality of her prose. She knows when to be plain and specific, and her metaphors and similes grow organically out of her created world: “That vast forest … had a reputation for being dark, but we saw daylight the entire time, black branches dividing the gray sky into panes, like the lead canes of a cathedral window.”

There is plenty of action as characters evade thugs, confront dragons, and give chase through back alleys, but Hartman trusts her material to sustain a varied rhythm. As Seraphina might put it, for every volta there is a pavane.

Fantasy novels are rife with invented language; good ones teach us how to read them as we go along. As we encounter the deliciously creative lexicon of Seraphina’s world we start to become bilingual.

For example, clothing plays an important role in the plot. (Without giving too much away, cross-dressing comes into it.) To give us a sense of what the characters are wearing, Hartman mixes antique words such as  “kirtle” and “surcoat” with the tasty and unusual “houpelande.” She also builds language in a Tolkienesque way. A dragon in human form is a saarantras; its plural form is saarantrai, its short form saar, which also functions as a form of address. By the time we get to ityasaari, the term for the taboo state of being a half-dragon, we’ve been in the immersion class long enough to take it in stride.

Finally, the ultimate challenge of young adult writing: is there a new way to describe a first kiss? Can one avoid the organ recital of pounding this and thudding that? In Hartman’s hands, it’s dragon lore meets Walt Whitman: “And that is when I know that I will kiss him, and the very thought of it fills me with … well, it’s as if I have just solved Skivver’s predictive equations or, even better, as if I have intuited the One Equation, seen the numbers behind the moon and stars, behind mountains and history, art and death and yearning, as if my comprehension is large enough that it can encompass universes, from the beginning to the end of time.”

If this is what love’s first blush is like for the saarantrai, then the startling and somehow comforting idea we are left with from Seraphina is that, perhaps, we’re all dragons under the skin.