Grandible does not want Neverfell to grow up. He wants to keep her cloistered because he enjoys her companionship, intelligence, and lolloping ways. He hasn't prepared her for the outside world and when she meets it she is naive and manipulated. He has her wear a mask and she thinks it is to hide her ugliness, but it is to hide her face. When a rabbit escapes their home, Neverfell's face is exposed to the autocratic world of Caverna and she gets swept up in a court of intrigues full of assassins and usurpers.
This coming-of-age story shows Neverfell not only discovering the world and making her place in it, it shows the parent, Grandible, that won't let go of a child and push him or her toward independence. Because she wasn't prepared she is ill-prepared for the world of courtiers. Grandible is melancholy after she is gone and clearly loves and misses her: "There was no red-haired sprite to scamper along beside him now, her babble as bothersome as an itch." Her character arc goes from the naive, manipulated child that trusts everyone to a young woman that makes decisions to try and control her own destiny.
The world building in Caverna is set up as an autocracy with an authoritarian system in place. People with money can afford to buy "faces"; that is, they are tutored on more than one expression. Drudges are the group of people at the bottom of the economic rung that have the unpleasant or servant jobs that keep the city cogs running smoothly so everyone has water, food, and sanitation; they are the marginalized people that suffer exploitation and injustices. History shows how oppressors try to silence the downtrodden by not letting them read, vote, go to school, etc. In Caverna, this is taken further for Drudges can't even express anger on their faces. They have only one facial look and it reflects obedience and happiness even when they are seething inside. When Neverfell discovers this underworld she becomes disillusioned with Caverna and the Grand Steward thinks it mars her face.
Magic comes in the form of magical cheeses and wines. The cheeses can be like dynamite and their volatility is dangerous. Wine is used to make people forget or as a poison meant to kill. Neverfell has no memory of her time living above ground with a family. She has a form of amnesia and can only remember bits and pieces of the world she came from before she was five when she was found by Grandible floating in a tub of cheese curds. Part of the plot's mystery is her uncovering her past. Other Caverna magic is in light-emitting, human-eating plants that give off oxygen and help keep the air fresh underground. Magic can be good or evil and depends on how it is used by a person. The lunatic Cartographers are mapmakers that study Caverna. If a person listens to a Cartographer too long he or she will go crazy. Hardinge has a djinn for an imagination and does not disappoint as she lets it go full tilt.
The Grand Steward runs the autocracy and his character is like a mixed potion of Alice in Wonderland's Red Queen and Dr. Jekyll and Mr. Hyde. The Grand Steward never sleeps and rests the left or right-side of his brain, literally, every 12 hours. When his right eye is open, the right-side of his brain is logical and clear with his left eye closed and sleeping. Likewise when his left eye is open, the left-side of his brain makes impulsive and unpredictable decisions while his right side sleeps. The two have been at odds with each other for decades and he maintains a constant state of wakefulness to be aware of assassination attempts. The Grand Steward has lost his curiosity of the world and has reigned for five hundred years. When Neverfell becomes his food taster she shows him the world through the eyes of youth where possibilities are infinite and new experiences are like steam rising from a hot spring. He describes his joy when noticing Neverfell's genuine admiration of him and long-forgotten feelings stirred by her smile.
People under the mountain get out of clock or lose track of their night and days suffering from insomnia. "She was out of clock, maybe further out of clock than she had ever been before. She could feel her mind pulling loose like knitting, the neat stitches of her artificial days unraveling to become one mangled thread." They are out of clock with their feelings as well as the relationships the Cavernians have with each other. This is best seen in the budding friendship between the twelve-year-olds, Zouelle and Neverfell. Zouelle only knows how to manipulate and be ruled by fear from adults. She learns how to feel through Neverfell, but more importantly how to trust and be honest. Even though she is offered power, she rejects it because she wants to live in truth, not lies, and have relationships based on love and trust.
The theme of truth and lies has been in every Hardinge book I've read and this one is no different. Caverna is a land of lies and no trust. Neverfell cannot lie and represents truth. Lies corrupt and cause unhappiness. After seeing the Drudges situation, Neverfell needs a facesmith to smooth out her disillusionment or the Grand Steward will kill her. People cannot express how they really feel, but Neverfell can only express what she feels; this makes her a weapon for power in the wrong hands. The Drudges cannot show their outrage at their inhuman treatment. The courtiers cannot show their disagreement with the Grand Steward or they will be killed. Like any autocracy, those that oppose the dictator are killed. Neverfell cannot fake anything. She has to be genuinely convinced that someone will improve the injustices Drudges face every day. The entire society is based on hypocrisy. I didn't think this came together quite as clearly as it could have, but it is implied and readers can make their own conclusions. The lying causes many deaths and gives the tale a dark undercurrent, "...tense calm tipped over into blood and chaos."
Neverfell changes from being manipulated by others to one who takes control of her life leading others. She is more interesting than the hero who has powers handed to him or her without a struggle and then saves the world. Hardinge's characters are flawed and more authentic as a result. They beat seemingly impossible odds like in the hero formula, except they make mistakes, use their brains, have courage, and take risks.
Hardinge uses descriptive titles for characters to make them come alive with verve. The Kleptomancer is a thief who disappears like the best of wizards. Neverfell, a girl that always falls into trouble, lives in a world like Neverland. Childersin uses children. Madam Appeline, sounds like Madeline pronounced the French way, Mad-Leen (and yes, she is a bit mad). Grandible, the cheesemaker, makes the grandest, most edible cheeses that are dangerous and can explode. Facesmiths are like blacksmiths except they teach others to make faces. Caverna is like a character rather than a city described with stalactites as teeth.
This narrative is a simmering pot of similes and metaphors. "Zouelle had forgotten how tiring it was listening to a Neverfell at full pace, like being bludgeoned with exclamation marks." "She lay there with her eyes closed as if sleep were a shy creature that might venture out if she played dead. But every time it seemed to be drawing closer, some loud thought would crash and blunder through the undergrowth, putting it to flight." That is a good description of me trying to sleep during the mad month of May. You teachers know exactly what I'm talking about. Take flight with Hardinge's imagination and get bludgeoned by her figurative language. It's worth it.