Demonglass

The second book in the Hex Hall trilogy opens at Hecate Hall, a reform school on the remote Graymalkin Island for Prodigium, the collective term for witches, shapeshifters, faeries, and vampires. Sophie Mercer, a teenager who discovered the previous semester that she is a demon, nearly drowns during a class exercise when a magically protected pond detects her demonic nature. She surges free using her powers and sees a man on the pier: James Atherton, her father and head of the Prodigium Council, the governing body for all Prodigium, whom she has never met in person.

In the headmistress's office, Sophie's father, her mother Grace, and headmistress Mrs. Casnoff review the previous semester: Sophie discovered she is a demon; her great-grandmother Alice, also a demon, killed Sophie's classmate Elodie Parris before Sophie killed Alice with demonglass, the only substance lethal to demons; and Archer Cross, a warlock Sophie had feelings for, was exposed as a member of L'Occhio di Dio (The Eye), a group of demon hunters. Sophie demands the Removal, a dangerous ritual that strips a Prodigium of their powers, so she will never become a monster like Alice. Her father proposes a deal: Sophie will spend the summer with him in England, and if she still wants the Removal afterward, he will allow it. Sophie agrees on the condition that her best friend Jenna Talbot, a vampire, comes too. Her father arranges for Cal, the school's 19-year-old groundskeeper and healer, to join them, then reveals that Sophie and Cal are betrothed through Prodigium custom. Sophie confronts Cal, and they agree the arrangement need not be serious. Before departing, Sophie sees Elodie's ghost look directly at her and nod, something impossible since ghosts at Hecate cannot perceive the living. On the ferry, Sophie feels a powerful premonition that the three friends will never return together.

The group arrives at Thorne Abbey, a massive English country estate serving as the Council's temporary headquarters. Sophie senses two other demons among the welcoming party, a teenage boy and girl, and is stunned. Her father introduces the remaining Council members: Lara Casnoff (Mrs. Casnoff's sister and his second-in-command), Kristopher (a shifter), Roderick (a faerie), and Elizabeth (a werewolf). The Council normally has 12 members, but only five survive. The demon teenagers, Nick and Daisy, have endured multiple assassination attempts and have nowhere else to go.

In the library, Sophie discovers Virginia Thorne's grimoire, a book of powerful dark magic locked under a protective glass case. Her father explains that Virginia used a ritual from the grimoire to transform Alice into a demon decades earlier, during a war between Prodigium and The Eye. He begins training Sophie to control her immense but unfocused powers, including teleportation and raw destructive force, teaching her to channel magic by anchoring it to a human memory or emotion. Demons possess godlike power but human minds and souls, he explains, and if the human side loses control, the magic overwhelms the person, as happened with Alice. This discipline, he argues, makes the Removal unnecessary.

Her father also reveals that The Eye burned Council Headquarters in London two months earlier, killing seven members, which explains the relocation. The Eye has allied with the Brannicks, an ancient line of white-witch descendants who also hunt Prodigium. Nick and Daisy's existence, proof that someone is raising demons again, has pushed all sides toward war. He urges Sophie to keep her powers for self-defense, since she will remain a target as his daughter regardless.

One night, Nick and Daisy take Sophie and Jenna to a Prodigium nightclub in London, traveling via the Itineris, a magical portal in an abandoned corn mill on Thorne's grounds. The Eye raids the club. During the escape, Archer grabs Sophie in an alley, shields her from a fellow Eye member, and presses a gold coin into her hand (a magical tracking device), telling her he will find her. Sophie hides the encounter.

Sophie's father secretly enlists her to help open the grimoire's sealed case, hoping to study the possession ritual and trace who created Nick and Daisy. The process requires blood magic and the combined power of two demons. When the glass dissolves, they discover the ritual page has been torn out. Later, the coin pulses with a vision of Archer waiting at the corn mill. Sophie agonizes but chooses not to go, placing loyalty to her father above her desire to see Archer.

Sophie's 17th birthday party ends in disaster when a magically targeted gift explodes, embedding demonglass in her shoulder. Archer, disguised as a waiter, is secretly present and tells Sophie he has critical information about Nick and Daisy. They agree to meet at the corn mill after her father leaves on a trip. At the meeting, Archer arrives with a sword and a protective golden chain necklace stolen from Hecate's cellar, which he gives to Sophie. He uses the Itineris to transport them to the far side of Graymalkin Island, where they discover a massive crater carved with symbols from the grimoire, surrounded by scorched trees saturated with dark magic: proof that demon-raising rituals are being performed at Hecate. Archer reveals that six students have disappeared from the school over 18 years, their parents placed under memory-altering spells. Three ghouls, reanimated guardians, attack. Sophie discovers she can command the dead by channeling magic through the earth and destroys them. Back at the mill, a farewell attempt collapses into a passionate kiss, and Archer admits he kissed her because he wanted to, not as an assignment.

Sophie tells her father about the site, omitting Archer's involvement. That evening, Daisy undergoes a full demonic transformation and attacks Sophie. Lara stops Daisy with a single command word, revealing her control over Daisy and confirming she performed the possession ritual. Sophie's father explains he cannot arrest the Casnoffs without proof, since blood oaths, binding magical agreements among Council members, prevent him from acting on suspicion alone.

Elodie's ghost writes a warning on Sophie's bathroom mirror: Nick is at the corn mill, and Archer is in danger. Sophie teleports to the mill and finds Archer dying from Nick's attack. Unable to heal him, she brings Cal, who saves Archer but is furious, revealing genuine romantic feelings for Sophie. Her father, Lara, and the remaining Council members arrive, having traced Cal's healing magic.

At the hearing, the Council sentences Archer to execution and Sophie to the Removal, citing her unprecedented powers, including what they describe as an unconscious necromantic binding of Elodie's ghost across an ocean. Her father intervenes, falsely claiming he ordered the investigation, and cedes his Council position to Lara. Lara reveals the Casnoff family's generational agenda: Lara and Mrs. Casnoff's father, Alexei Casnoff, orchestrated Alice's original transformation, manipulated Sophie's grandmother Lucy into killing Lucy's husband, then disposed of Lucy, all to weaponize the Atherton demon bloodline. Mrs. Casnoff confirms that a secret demon army exists beyond Nick and Daisy.

Sophie's father undergoes the Removal, losing his powers permanently. As Sophie is taken to her own Removal, chaos erupts: Nick, fully transformed, has killed nearly 20 people, and The Eye attacks Thorne Abbey. Kristopher is killed. Sophie finds Jenna's shattered bloodstone, a talisman that protects vampires from sunlight; its destruction implies Jenna is dead. Elodie's ghost leads Sophie through a secret passage to the garden, where Thorne Abbey stands engulfed in flames. Cal appears and tells Sophie to use the Itineris to find Aislinn Brannick, leader of the Brannick hunters, because Sophie's mother is with them. Cal kisses Sophie, then runs into the burning mansion to rescue her father and Archer. Sophie walks to the corn mill, picks up Archer's abandoned sword, and feels a psychic certainty she will see him again. Clutching the sword and wearing the protective necklace Archer gave her, she steps into the Itineris.