Dedicate Initiates Rosethorn and Myrrhtide have been summoned to the Battle Islands because of problems with dying plants and poisoned water. Rosethorn decides that Evvy should come along too, to help her overcome lingering trauma from Gyongxe. And, as it turns out, what's going on in the Battle Islands is something only Evvy's magic can deal with.
Tropes:
- 11th-Hour Superpower: Right before going to confront the volcano spirits for the last time, Evvy digs deep enough in the Earth to find solid diamond and armor herself in it. Unlike most examples, it doesn't give her the power to actually win, but it does keep her alive long enough for the islands to save her.
- Armor-Piercing Question: When Oswin wants to go back for Meryem, Azaze asks him "What of your other eleven children?". Combined with one of his sons pleading for him, it convinces him to turn back.
- Big Damn Heroes: When Flare and Carnelian turn on Evvy in the climax and are on the verge of melting her entirely, Luvo shows up with the spirits of every island in the Battle Islands, who force the volcano spirits to go detonate elsewhere.
- Call a Human a "Meatbag": Due to her traumatic experiences with people and animals, Evvy starts to dismissively refer to living beings as "meat creatures" as Luvo does. Her character arc is learning and accepting that she is a meat creature too.
- Cast from Calories: Whenever Evvy or another mage exhausts their magic, they eat ravenously.
- Chekhov's Skill: The first time Flare and Carnelian hear Luvo's voice, they are utterly terrified, not knowing that he can't actually hurt them. Luvo, Starns, and the other islands use this to drive them off in the end.
- Cold Equation: With the volcano due to go off at any moment, Rosethorn and Azaze determine that they can't afford to spend any time going back for stragglers. Evvy can't bring herself to abandon Meryem and the other two children, but Rosethorn, who is absolutely necessary for the escaping ships, is forced to abandon Evvy on the island.
- Continuity Nod: Nory is heavily implied to be the daughter of Pauha, the pirate queen from Tris's Book.
- A Day in the Limelight: This book is all about Evvy. In fact, it's the only Circle book in which the familiar quartet of Sandry, Tris, Daja and Briar don't appear.
- Fantastic Racism: Nory and Treak both dismiss Evvy as a stuck-up pampered snob because she's a mage and that she doesn't know what "real" people have to suffer. Evvy, who was sold as a slave by her own parents, struggled to survive on the streets, and lived through torture and war in Gyongxe, is not amused by their presumption.
- Genius Loci: Starns itself turns up in the climax, along with the spirits of the other islands, to drive the magma away. They were resigned to being destroyed until Luvo convinced them not to.
- Holier Than Thou: Dedicate Myrrhtide accuses the poor of being parasites trying to feed off the Temple's generosity, all while being unduly demanding on them himself. Luvo calls him on it and he gets better.
- Immortal Immaturity: Flare and Carnelian may be ancient volcano spirits, but they act like nothing more than petulant children forever looking for their next distraction and whining that they want to go outside now. But with their exceptional power and willingness to melt anyone they don't like, there isn't much Evvy can do besides play along. The islands put them in their place at the end.
- Jerk with a Heart of Gold: Myrrhtide, who Evvy calls "Fusspot", is rather high-strung but ultimately does care about people, doing his best to get the locals out of harm's way.
- Kick the Morality Pet: One of Oswin's children Meryem gets rather attached to Evvy, imitating her and defending her against the other children. However, when she starts whining at the wrong time, Evvy snaps and tells her that she isn't her friend and to run along. Evvy feels regret, but reasons to herself that she can make it up to her after she's done with her magic. Except that Meryem impulsively decides to head back home for a pretty rock to make Evvy like her again, which causes Evvy to go back for her and nearly gets them both killed.
- Misanthrope Supreme: Evvy comes dangerously close to this, believing that all people are selfish and cruel deep down with Rosethorn and Briar being rare exceptions, and telling Rosethorn to abandon the people of Starns because they don't mean anything to her. It takes her the whole book to admit to herself she does care about people, she's just terrified of losing them.
- Never My Fault: Nory loses track of Meryem in the chaos, and blames it on Evvy for upsetting her. And then ditches the other eleven children she was watching to try and go get her.
- Nice Job Breaking It, Hero:
- Evvy telling Meryem off at the exact wrong moment causes Meryem to head back to her house.
- Angered by Evvy trying to fight the volcano, Rosethorn impulsively tells her that apathy to others is the first step to being a destroyer. She takes it back almost immediately and restates that "it wasn't fair to her", but Evvy takes it to heart and tries to sacrifice herself to save Starns.
- Evvy tampering with the volcano spirits very nearly causes them to come up right beneath the fleeing refugees.
- Not Now, Kiddo: While Rosethorn and Azaze believe her immediately, the rest of the village Council are angered that they've been called, believing that Evvy's warning about the volcano is just a girl lying her way out of trouble. It takes Tahar confirming it for them to take it seriously.
- Past Experience Nightmare: Evvy and Rosethorn both have nightmares of what they went through during the war in Gyongxe.
- Reasonable Authority Figure: The headwoman Azaze believes Evvy immediately when she tells her about the volcano, reasoning that Evvy has never acted like this before, and evacuates the entire island with grace and poise.
- Relocating the Explosion: In a rather unusual take on the trope, Evvy manages to relocate a volcanic eruption, thereby causing the birth of a new island, through a combination of persuasion, trickery and help from the spirits of other islands.
- Shell-Shocked Veteran: Evvy and Rosethorn are both traumatized by what they went through in Gyongxe.
- Simultaneous Arcs: This book takes place while Sandry, Daja, Tris and Briar are travelling to Namorn in The Will of the Empress.
- Taking the Veil: At the end, Evvy decides to become a novice at Winding Circle.
- Unequal Rites: Myrrhtide provides one of the series' few examples of ambient mages looking down on academic mages rather than the other way around, dismissing Tahar and Jayat as worthless amateurs for their lack of learning. Luvo gives him one hell of a "The Reason You Suck" Speech for it.
- Wake Up Fighting: Evvy attacks Myrrhtide once when he tries to wake her up because he disregarded Rosethorn's warning about not doing so because of what happened to her during the war.
- Youth Is Wasted on the Dumb: A cascading example. In the middle of evacuating, Evvy snaps at Meryem and Meryem decides to run back home to get her a rock even though eruption is imminent. She is followed by Nory who abandons the other 11 children to get her, Jayat who has a crush on Nory, and Evvy, who feels guilty and thus decides to try one last time to pull out the volcano spirits. If it hadn't been for the other islands arriving to save Evvy, all four of them would have died pointlessly and Evvy's meddling might have set off an eruption right beneath the escaping ships.
