Amy Thomsett is sent to Drearcliff Grange School after she develops a tendency to float in the air when she's excited. Her first term is relatively uneventful, not counting the incident when her roommate is kidnapped by a Hooded Conspiracy and Amy forms a secret society, the Moth Club, to rescue her. Second term brings several changes, and a menace that may threaten the entire world.
The novel is set in the same world as Newman's Diogenes Club series. Part of it was first published as a novella in the collection Mysteries of the Diogenes Club. It was followed by a sequel, The Haunting of Drearcliff Grange School, in 2018.
This novel provides examples of:
- Academy of Adventure: Drearcliff Grange School, as one might expect when the school is deliberately gathering in students with supernatural abilities or other forms of weirdness. Being built on a weak spot in the wall between dimensions probably doesn't help.
- Adults Are Useless: As required for the boarding school adventure genre, so that the girls can save the day. Most of the teachers are just not up to dealing with the menace that engulfs the school. A couple are actively collaborating. Miss Kaye, who is an undercover agent of the Diogenes Club, gets nobbled by a combination of bad luck and enemy action just when she might have been useful. The headmistress deliberately stays out of the way because she wants the Unusual students to step up and discover their potential.
- Alien Sky: The Purple, an alternate dimension Amy visits several times in the story, is lit by three moons.
- And the Adventure Continues: The book ends with Amy arriving for a new school year and immediately encountering a new mystery for the Moth Club to investigate.
- Animal Theme Naming: The Moth Club's codenames are all types of moth, as chosen by the lepidoptery enthusiast Amy. Naturally, their nemesis, Antoinette Rawley Rayne, is named for a different kind of insect.
- Assimilation Plot: Rayne's Black Skirts
- Battle Butler: Professor Rayne has a hulking battle chauffeur who turns out to be a shaven yeti.
- Boarding School of Horrors: Combines this with Superhero School for a Deconstruction of Girls' School stories such as The Silent Three. The main character is warned that the prefects can punish her for having a red mark on her face by slapping her (and can continue to do so as long as she continues to have red marks on her face), and will already have ritually burnt the doll in her luggage at the stake (as it turns out they haven't, they're waiting to torture it in front of her). But then that gets deconstructed, when we're told that after three weeks she no longer sees the school as either good or bad; it's simply how things are.
- Brown Note: Antoinette Rowley Rayne's mind-controlling skipping rhyme.
- Bullet Catch: Laurence catches a cannonball by opening her "purple pocket" directly in its path. Her turning this trope into Catch and Return, duplicating the projectile and releasing it from the pocket towards the Black Ants' pirate ship, is what finally wins the battle for the Remove.
- Call-Forward: The weather research station in Sutton Mallet, mentioned briefly near the end, is the main setting of the Diogenes Club story "Cold Snap" which features Amy's son as a protagonist.
- Character Overlap: Several of the characters have previously appeared in the Diogenes Club series, most obviously the undercover teacher Miss Kaye, who is a main character in that series. Amy herself has been mentioned a few times in her adult guise as a moth-themed costumed crimefighter, including a cameo in "Sorcerer Conjurer Wizard Witch". Fish-girl Janice Marsh, as an adult, is a key character in "The Big Fish" and "Another Fish Story". Miss Borrodale, the science teacher, appears as a schoolgirl in "Richard Riddle, Boy Detective in 'The Case of the French Spy'".
- Chekhov M.I.A.: Early in the book it's mentioned as a passing oddity that a student named Enid ffolliott has been missing for two years but is still called on during the weekly roll-call because she never officially left the school. She makes a dramatic reappearance later in the story.
- Continuity Nod:
- There are several references to the Splendid Six, the superhero team featured in "Clubland Heroes". Lucinda Tregellis-d'Aulney, the Aviatrix, is a former Drearcliff girl, and her flying ability gets compared to Amy's.
- "Poppet" Dyall is implied to be a changeling like the girls in "Angel Down, Sussex" and "The Gypsies in the Wood". In one scene, she's seen reading a copy of Uncle Satt's Miscellany, the children's magazine from "The Gypsies in the Wood" that prints fairy stories inspired by real fairy encounters.
- Amy is enough of a fan of crimefighter Dr. Shade to follow his exploits in magazines. Fifty-odd years later, their son Jamie Chambers will have an adventure of his own in "Cold Snap".
- Crying Wolf: One of Amy's schoolfriends, Smudge, is constantly telling wild stories. Then another friend gets kidnapped by sinister hooded figures, and they go to report this to the staff: "Smudge told the story first, which was a disaster." Amy reflects later that it's a pity for Smudge that the one time one of her stories is true, nobody who wasn't there believes it.
- Daddy's Little Villain: Antoinette Rowley Rayne has been groomed and possibly empowered by her mother as part of a world domination plan.
- Distant Finale: A chapter where Amy returns to the school as an adult for a school reunion. In a twist, due to timey-wimey caused by a Thin Dimensional Barrier, it's not the last chapter of the book.
- Everyone Calls Him "Barkeep": The school's custodian, known to one and all as "Keys" because she carries an enormous bunch of keys for every door in the school.
- Famous, Famous, Fictional: A tract on reshaping human society along purportedly scientific lines is said to have drawn favorable critical notice from H. G. Wells, G. K. Chesterton, George Bernard Shaw, and Roderick Spode.
- Fire/Ice Duo: Frost and Thorn, who have ice and fire powers respectively, become friends, and are indicated to become a supervillain duo as adults.
- Flash Forward: Amy has one at the climax of the novel, when she dives into the Purple to save Dora Paule, seeing what will become of herself and her friends as adults.
- Flight: Amy's main power, though as she's the first to point out it's not exactly flight: she can only float, susceptible to passing breezes and with no control over her lateral movement. In the final confrontation, she realises that her other power, which lets her move light objects with her mind, can also be applied to herself, giving her full control over her movement in the air.
- Genteel Interbellum Setting: Some unspecified time between the World Wars.
- Gratuitous French: Exaggerated with Gryce, the head girl, who peppers her speech with French words and phrases to the point that at times her dialogue consists of the occasional lonely word of English floating in a sea of French.
- Great Big Book of Everything: The Headmistress keeps a school-specific one locked in her office, which contains maps and other information detailing the school and its grounds, including the secret tunnels — and explicitly updates itself by some mysterious means so that the maps and other information are always accurate. "Know-It-All" Knowles uses her Photographic Memory to memorise the book so the Unusuals can navigate the secret tunnels, and later complains that she can feel her memories changing as the book updates.
- Green Thumb: Fleur Paquignet has an affinity with plants, and can cause them to grow in inhospitable conditions and at unnatural speeds.
- Gym Class Rope Climb: The rope climb is a trope-standard pit of horrors, but Amy avoids the worst of it by judicious use of her floating-in-the-air superpower.
- Hero of Another Story: There are occasional reminders during the earlier parts of the book that the school has plenty of students apart from Amy and her friends, some of whom are having their own Boarding School Story Experiences; less so in the later part of the book where the Reign of Rayne becomes the defining feature of school life. The circumstances of Enid ffolliott's return suggest that what she was doing during the two years she went missing was adventurous and possibly world-saving, although we don't get many details.
- I Just Want to Be Normal: Gould, the Wolf-girl, tries to become one of the Black Skirts in hope of fitting in. She learns the hard way that Rayne only kept her around to use her tracking abilities to try to locate the fugitive Headmistress.
- Insignia Rip-Off Ritual: Amy is forced to undergo one when she is kicked out of Desdemona House for refusing to bow to the new regime.
- Insistent Terminology: "Sea-raiders", not "pirates".
- Knight of Cerebus: The first section of the book is light-hearted and cheerful for the most part, with the Hooded Conspiracy being foolish and easily outwitted. Then Antoinette Rowley Rayne appears on the scene, and things become much darker.
- Learnt English from Watching Television: Kali, who is from a remote part of Asia, learned English from American pulp magazines, and litters her speech with stereotypical gangster slang.
- Liquid Assets: "Shrimp" Harper has the ability to "breathe in" the life force of others, leaving them feeling tired and run-down.
- Meaningful Name:
- Knowles has the power to know vast amounts of information.
- Frost is An Ice Person.
- A girl named Fleur has Green Thumb powers.
- Mind over Matter: Amy develops a telekinetic ability that lets her cause other things than herself to float (or to become heavier than usual) and eventually to move them about at will.
- Minor Crime Reveals Major Plot: The abduction of Kali turns out to be the prelude to an attempt to take over the planet with mind-control... which then itself gets hijacked into an attempt by extra-dimensional Eldritch Abominations to invade the mortal plane.
- My Brain Is Big: In the Purple, where the Unusuals' appearances change to reflect their natures, the psychic Dora Paule appears with an oversize cranium and undersized rest of her body.
- Mysterious Purple: Very mysterious; the majority of the novel's creepy, otherworldly, and enigmatic stems from a weird other dimension called "The Purple."
- Mythology Gag:
- A quartet of school chum refer to themselves as "the Forus", short for "the four of us". Newman's novel The Quorum revolves around a quartet of school friends who called themselves "the Forum", because there were four of 'em.
- The running gag about a former student who was named Marion, but nobody can remember whether Marion was her first or last name, is a reference to Newman's novel Life's Lottery, where the protagonist is named Keith Marion and in one chapter is also a character named Marion Keith.
- Non-Indicative Name: "Frecks" Walmergrave has no freckles. She had Youthful Freckles when she acquired the nickname; by the time Amy meets her the freckles are long gone but the nickname remains.
- Noodle Incident: The Distant Finale includes a Long List of noodle incidents, as adult Amy reflects on the adventures she's been involved in since forming the Moth Club. It takes up over a page.
- Older Than They Look:
- Dora Paule is a student in the Sixth Form. She's been in the Sixth Form for over twenty years.
- The headmistress, Dr. Swan, has been headmistress since the school opened in 1877, over forty years ago, and if the annual school photo is any indication she hasn't aged a day in all that time.
- One-Gender School: Drearcliff is a girls' school. Even the staff is nearly all female in the wake of the Great War.
- Only the Pure of Heart: Frecks's chainmail coif, inherited from her sky-knight uncle, will shield its wearer from harm or hostile influence including Rayne's, but only so long as they remain good and true.
- Photographic Memory: "Know-It-All" Knowles can retain any information in full detail after reading it once, though it fades away after about a month. It actually goes beyond just memory; she understands everything she memorises, even if it's a subject she has no grounding in, and if it's something like a training manual for a skill, she acquires the skill without any need to practice it.
- Planimal: Among the weird sights Amy sees in the Purple are living wolves with bodies made of wood.
- Portrait Painting Peephole: There's a portrait of the Headmistress in every building in the school, and they all have removable eyeholes and secret passages behind them that let the Headmistress keep an eye on things unnoticed.
- Poster-Gallery Bedroom: The section of wall over Kali's bed is decorated with photos of American gangsters, boxers, and the kind of movie actor who plays gangsters and boxers.
- Power Dyes Your Hair: Dilys Frost starts out with a white streak in her black hair. It gets wider every time she uses her power, and she ends up with a black streak in her white hair.
- Power Incontinence: Harper and Dyall are outcasts because their uncontrollable powers have unpleasant effects on anyone around them. Harper is implied to have nearly killed her own mother as a baby due to her energy-vampire ability.
- Psychic Nosebleed: Amy sometimes gets one from early attempts to use her telekinesis.
- Puppeteer Parasite: One of the students is in a coma while a parasitic maggot in her brain drives her body around.
- Ragtag Bunch of Misfits: The Unusuals form one when they're forced together by being the only people still capable of resisting the Reign of Rayne.
- Rubber Man: Devlin can elongate her neck and limbs and twist them as if they lack bones.
- Rule of Three: The Black Skirt girls do everything in groups of three, to the point where some of the trios acquire gestalt nicknames: Cerberus, Chimera, Ghidorah, Triceratops.
- Shark Pool: Mention is made, in the context of a girl whose father is a crime boss, of a man named "Singapore Charlie" whose business is providing criminal masterminds with deadly animals for their alligator pits and other death traps.
- Sherlock Scan: In the Distant Finale, Naisbitt does one on Amy to demonstrate the detective ability she's grown into, deducing Amy's recent activities in remarkable detail from small traces on her clothing.
- Sinister Minister:
- The creepy school chaplain "Ponce", who turns out to be even worse than rumour suspected.
- It may be a requirement for the position. His successor, who arrives in the final chapter, is implied to be a vampire.
- Snowlems: Frost calls up increasingly-larger copies of shako-topped snowman Captain Freezing over the course of the winter, ultimately manifesting an animated version for the battle in the caves.
- Stepford Smiler: "Perky" Palgraive smiles all the time, no matter what the provocation (and several of the prefects consider it a challenge to wipe the smile off her face). This is because she's a Meat Puppet for a parasitic maggot that hasn't entirely got the hang of fine motor control or the nicer points of human interaction.
- Stupid Jetpack Hitler: In the Distant Finale, set during World War II, Amy recalls taking part in a raid on a Nazi "dark physics facility" that was trying to revive a carnivorous dinosaur frozen in a glacier, and one of her colleagues dealing with "a squadron of Tiger tanks controlled by the bottled brains of dead Afrika Korps commanders". It's also hinted that the Nazis borrowed from Rayne's mental assimilation techniques.
- Superhero School: Drearcliff Grange is a 1920s girls' school which takes "Unusual" students. The headmistress makes it clear that she doesn't much care if one of her girls becomes a supervillain instead of a superhero, just so long as she makes use of her talent and doesn't settle for being mundane.
- Super-Speed: "Light Fingers" Naisbitt's ability. To begin with, she mainly uses it to pick people's pockets or to complete tedious tasks (sewing, copying lines) lickety-split. Later, she discovers that it also endows her with "quick thinking", the ability to develop complicated theories and plans in a moment, and the Distant Finale indicates that she will go on to become a successful detective.
- Tear Off Your Face: The Hooded Conspirators abduct Rose with the intention of doing this to her as a ritual sacrifice.
- Theme Twin Naming: Jacqueline "Shrimp" Harper has a twin brother named Jacques.
- Thin Dimensional Barrier: There's one in the secret tunnels under the school which is important to the Big Bad's plans.
- Unusually Uninteresting Name: When Amy and her friends form a secret society to rescue Kali from the Hooded Conspiracy, they suggest names like "the Three Good Girls" and "the Scarlet Slippers". Amy suggests "the Moth Club". When her friends ask what kind of name that is for a secret society, she says it's one that would cause most people to instantly lose interest.
- Vampiric Draining: "Shrimp" Harper has the ability to "breathe in" the life force of others, leaving them feeling tired and run-down.
- Walk on Water: Light Fingers does the super-speed run-on-water version during the climactic battle.
- We Didn't Start the Führer: The Third Reich is implied to have been inspired by, or at least to have borrowed from, Professor Rayne's ideas.
- Wolverine Claws: Professor Rayne wields a scalpel-tipped glove that crackles with sparks.
