Her Majesty's Royal Coven (her Majesty's Royal Coven, #1)

The novel is set in a contemporary United Kingdom where witches live in secret among ordinary humans, known as mundanes. The country's only government-affiliated coven, Her Majesty's Royal Coven (HMRC), traces its origins to a secret coven founded by Queen Elizabeth I and was formally established as a government department in 1869. Witches possess varying magical abilities: sentience (telepathy and telekinesis), healing, elementalism (control of natural forces), or oracle sight (prophetic vision). Rare individuals called adepts possess more than one gift. Male witches, called warlocks, are generally less powerful and belong to a separate organization, the Warlocks' Cabal.

A prologue set 25 years earlier introduces five young girls on the eve of their induction into the coven: Helena, the eldest and from a prestigious witching family; Leonie, only nine and the first witch in her family's living memory; Niamh and her identical twin Ciara; and Elle, granddaughter of the powerful oracle Annie Device. The following night, they are formally made witches in a blood ritual on Pendle Hill.

In the present day, the five have grown apart. Niamh, a powerful adept with sentient, healing, and elemental abilities, works as a veterinarian in Hebden Bridge, Yorkshire, grieving her fiancé Conrad, who was killed in a civil war instigated by the warlock Dabney Hale eight years earlier. Helena is now the High Priestess of HMRC; her husband Stefan also died in the war. Leonie, living in London with her girlfriend Chinara, has founded Diaspora, a coven for witches and warlocks of color marginalized by HMRC's predominantly white hierarchy. Elle lives in Hebden Bridge, hiding her witchcraft from her mundane husband Jez.

The four women reconnect when Helena reveals an alarming prophecy. HMRC's oracles have foreseen Manchester in ruins, with the silhouette of Leviathan, the demon king of fear and one third of an unholy demonic trinity, looming over the destruction. The oracles link this vision to the Sullied Child, a prophesied male child who will invoke Leviathan and end witchkind. Helena believes they have found the child: a teenager who destroyed a school near Edinburgh with lightning and is now caged in Grierlings, HMRC's high-security prison.

Niamh visits the boy and makes telepathic contact through his terrified defenses. He gives his name as Theo and asks for help. Niamh persuades Helena to release Theo into her care; Helena assigns a security team led by Robyn Jones, a sentient witch. On Theo's first night at the cottage, he transmits a nightmare into Niamh's mind: a memory of a woman pushing an infant underwater. The nightmare triggers an earthquake, and Niamh discovers Theo possesses elemental, sentient, and healing abilities, one more gift than she herself has.

Niamh mentors Theo alongside Holly, Elle's 14-year-old daughter, whose sentient abilities have recently emerged. She consults Annie Device, who warns that oracles' visions are shaped by their tellers and that nothing is set in stone. During a field test at Malham Cove, Theo accidentally summons a flock of ravens that attack the group, exposing his dangerous lack of control. A romantic subplot develops as Niamh grows closer to Luke, a local deliveryman, though she feels unable to move on from Conrad. Helena, increasingly suspicious, sends her 15-year-old daughter Snow to Hebden Bridge to spy on Theo.

Holly confides to Elle that Theo has told her she is transgender. Niamh realizes this reframes everything: Theo's power levels align with female witches rather than male warlocks, and the dissonance of living in the wrong body may explain her volatile magic. Niamh meets Valentina, a trans woman and powerful elemental in Leonie's coven, confirming that trans women possess full witch-level power.

When Snow reports Theo's gender identity, Helena reacts with visceral rejection. She orchestrates a girls' night out so Leonie's brother Radley, head of the Warlocks' Cabal, can seize Theo from the cottage. Niamh discovers the abduction, takes the stimulant potion Excelsior, pursues the cabal van through the air, and secures Theo's release. She confronts Helena in a bitter argument: Helena insists covens are exclusively for women; Niamh counters that witches' magic transcends the body and declares she can no longer be friends with Helena unless Helena extends Theo kindness.

Helena's obsession deepens. Driven by unverified visions from a young oracle showing Theo atop pyres of dead witches, she visits Hale in prison and learns he once channeled the demon Belial to amplify his power. Helena seizes contraband texts on demonic invocation. She then visits Annie's cottage, knowing the oracle has foreseen her plans. Unable to risk Annie warning the others, Helena freezes the cottage to lethal temperatures. Annie dies of hypothermia. Niamh finds a single word in Annie's final diary entry: Ciara.

After Annie's funeral, Helena performs a demonic invocation following instructions from a seized text called The Gospel of Lilith. Belial enters her body, granting powers she never possessed. Under the demon's influence, she unknowingly frees Hale from Grierlings and assembles a strike force authorized to use lethal force against Theo. Her assistant Sandhya flees to warn Leonie.

Helena's forces teleport into Hebden Bridge, putting mundanes to sleep and sealing the town. Niamh flees with Theo and Luke, now unconscious from the sleep spell, but HMRC witches rupture the streets and flip her vehicle. Elle and Holly arrive to fight, while Leonie, Chinara, Valentina, and Sandhya breach the barrier from outside, driving back the attackers.

Niamh and Theo escape into the forest toward a magical water conduit at Annie's cottage, but Helena intercepts them. With Belial's power, Helena turns the stream to fire, trapping Niamh, and begins strangling Theo. Niamh transfers nearly all her remaining life energy into Theo through the water, and Theo undergoes a true physical transformation, her body reshaping to match her identity. Speaking aloud for the first time, Theo declares herself Theodora and fights Helena to a standstill. Remembering Annie's advice that water extinguishes fire simply by being water, Niamh summons a swarm of honeybees, exploiting Helena's severe allergy. The anaphylactic reaction forces Belial out of Helena's body, and Elle arrives to stabilize her.

Helena is tried and found guilty of betraying her coven, murdering Annie, and consorting with demons. Despite protests from Niamh, Leonie, and Chinara, she is executed in the Pipes, Grierlings' furnace chambers. Her last words are a plea for mercy so she can watch Snow grow up.

At the summer solstice, Holly, Snow, and Theo, now officially Theodora Wells, take the witches' oath under Moira Roberts, the Cailleach, or presiding witch leader, of Scotland. The oracles privately tell Niamh they foresee her as the next High Priestess. Snow confronts Niamh with a vow to return and destroy her. Leonie discovers that Radley has gone alone to hunt the escaped Hale and resolves to save him.

In September, Niamh visits Ciara at a safehouse in Manchester, hoping to honor Annie's dying wish by reconciling with her twin. Ciara had aligned with Hale during the civil war, and Niamh destroyed her mind in the conflict's climax, leaving her comatose. Now Ciara's hand twitches. She presses a small ruby, placed in her palm weeks earlier by the Belial-possessed Helena, into Niamh's skin. An azure flash reveals that Ciara has used the enchanted gem to swap their bodies. Inhabiting Niamh's body, Ciara smothers her former shell with a pillow, killing the novel's protagonist, and walks out wearing her sister's face.