Rebel Angels, the second installment in Libba Bray's Gemma Doyle trilogy, is set in Victorian England in December 1895 and continues the story of sixteen-year-old Gemma Doyle, a girl with supernatural powers tied to a hidden magical dimension called the realms.
The novel opens with a prologue narrated by Kartik, a young Indian man and novice of the Rakshana, a secret brotherhood that guards the realms. Masked elders condemn him for failing to prevent Gemma from shattering the Runes of the Oracle. These ancient stones sealed the realms' magic under the governance of the Order, a powerful group of sorceresses. With the runes broken, the magic is wild and accessible to any spirit, including forces allied with Circe, a rogue sorceress. The elders order Kartik to guide Gemma to the Temple, the hidden source of all magic, where she must speak binding words that would secretly cede control to the Rakshana. Once the Temple is secured, Kartik must kill her.
Gemma narrates the rest of the novel from Spence Academy, where she spends the final days before Christmas with her friends, the bold Felicity Worthington and the self-deprecating Ann Bradshaw. Gemma has been plagued by nightmares featuring Pippa Cross, their friend who died two months earlier in the realms. Felicity pressures Gemma to return to the realms, but Gemma lies, claiming she can no longer open the door of light, the magical portal, when in truth she fears her own power.
A new teacher, Miss McCleethy, arrives at Spence and draws suspicion by pausing at the sealed East Wing doors as if recognizing the place. Kartik warns Gemma that dark forces could seize the wild magic and urges her to find the Temple. That night, the three girls enter the realms and discover Pippa apparently alive and beautiful, claiming she chose not to cross the river to the afterlife. Pippa warns that the Rakshana covet the Order's power and volunteers to help find the Temple, but Gemma notices a disturbing expression on Pippa's face: hunger.
In London for the holidays, Gemma moves into her grandmother's house, where her father struggles with laudanum addiction. She meets Simon Middleton, the charming son of a viscount. Felicity takes Ann home, inventing a cover story that Ann is descended from Russian royalty. The girls visit their former art teacher, Miss Moore, who was dismissed from Spence, and share elaborate "stories" about the Order as fiction. Miss Moore listens with keen interest.
Gemma's brother Tom, a clinical assistant at Bethlem Royal Hospital, mentions a patient named Nell Hawkins who believes she belongs to the Order and that Circe is hunting her. Gemma visits Nell, who repeats cryptic instructions: "Follow the true path," "The Temple hides in plain sight," and "Beware the Poppy Warriors," shape-shifting knights the Order cursed to take the form of black birds.
The girls return to the realms, where Pippa introduces them to the gorgon, a massive serpent-haired creature bound to a ship that carries them to the Forest of Lights. There, Philon, an androgynous being, gives Felicity a bow and silver-tipped arrows in exchange for a future share of the magic. On the return trip, water nymphs nearly lure Gemma into the river before Pippa saves her.
Kartik takes a position as the Doyle family's coachman, arranged by the Rakshana. At a bookseller's, the girls follow Miss McCleethy to Bethlem and learn that the Order used anagrams to hide identities. Ann rearranges "Claire McCleethy" to produce "They Call Me Circe." Further journeys through the realms lead to the Caves of Sighs, where Asha, one of the Untouchables, a marginalized people inhabiting ancient ruins, paints protective designs on their hands to shield them from dark spirits.
Crises mount in London. Gemma rescues her father from an opium den on Christmas Eve. On Christmas morning, Kartik kisses her, but Gemma makes an insulting remark about not thinking of him as Indian, and he departs. At Felicity's Christmas ball, Gemma discovers that Felicity's father has been sexually abusing her, a revelation that permanently alters their friendship.
At a public event at Bethlem, Nell delivers a coded performance mapping the route to the Temple. She forces a shared vision on Gemma, revealing that a teacher called "Miss McCleethy" sacrificed three girls to a sea creature. Evidence builds against Miss McCleethy until the Rakshana kidnap Gemma with Miss McCleethy present. Miss McCleethy insists she is actually Sahirah Foster, an Order member who adopted the name as a decoy to draw out the real Circe. She reveals the Rakshana's binding words would give them control of the Temple and that Kartik was ordered to kill Gemma. Kartik confirms this but betrays the Rakshana by helping Gemma escape, sacrificing his only community.
Gemma flees to Miss Moore's flat and finds a farewell note using the same phrasing attributed to Miss McCleethy. She rearranges "Hester Asa Moore" to produce "Sarah Rees-Toome," and a final vision confirms Miss Moore is Circe.
After three days of illness, Gemma learns from Nell, who has fallen into a trance after Circe reached her, that Circe cannot bind the magic alone. The girls enter the realms one final time. Three ghostly girls lead them to a false temple, actually the lair of the Poppy Warriors, whose leader traps them in catacombs and exploits their deepest fears. Felicity kills the leader with an arrow, but water nymphs capsize their boat and drag Ann underwater. Desperate, Gemma brings Miss Moore into the realms, gambling that Circe's knowledge can help rescue Ann. They find Ann in the nymphs' lagoon and free her. Circe's tracker attacks, and Miss Moore is captured.
Gemma discovers the true Temple hidden in plain sight: the Caves of Sighs, home of the Untouchables. She steps through a waterfall to the well of eternity, a perfect circle of water showing past, present, and future. Miss Moore appears with the captive Nell, demanding Gemma share the Temple's power. Pippa, tempted by the promise of eternal life, shields Miss Moore from Felicity's last arrow. Nell communicates silently to Gemma: "Set me free." Gemma shoots Nell through the throat, a devastating act that strips Circe of her leverage. Gemma and Miss Moore plunge into the well, where Gemma kicks free and speaks her own binding words: "I place a seal upon the power. Let the balance of the realms be restored and let no one disturb their majesty. I bind the magic in the name of all who shall share the power one day. For I am the Temple; the magic lives in me." White light courses through her, and Miss Moore is trapped within the well.
With the wild magic contained, the magical illusion sustaining Pippa's appearance fades, revealing sharp teeth and milky white eyes. Gemma urges her to cross the river, but Pippa refuses and flees toward the Winterlands, a dark region of the realms, vowing the girls will regret this. Thousands of spirits cross the river at last. Nell, restored and smiling, waves goodbye before crossing to the other side.
Back in London, Gemma offers Kartik a new alliance free of the Rakshana. She confronts Miss McCleethy, who warns the Order will not surrender its power easily. Gemma returns Simon's pearl brooch, recognizing she cannot be the uncomplicated girl he wants. At Spence, Gemma reflects that she has bound the magic to herself and faces an uncertain future with the Order, the Rakshana, and the Winterlands, where Pippa now dwells as a potential enemy. Watching a leaf carried skyward by the wind, she finds comfort in her friends and in stretching toward something just out of reach.