The Robin on the Oak Throne

The second installment in the Oak & Holly Cycle picks up five months after The Wren in the Holly Library. Kierse McKenna, a twenty-five-year-old thief and the last known will-o'-the-wisp, a rare type of Fae with absorption magic, has fled New York for Dublin with her best friend Gen, a newly discovered High Priestess whose role grants heightened magical power. In the preceding volume, Kierse stole the Spear of Lugh, one of four legendary Celtic magical objects, and discovered her Fae heritage, all while falling for Graves, a centuries-old warlock who hid her identity from her.

The story opens at the Beltane festival at Versailles, where Kierse infiltrates the celebration to steal a goblin-made amethyst bracelet from Queen Aveline of the Nymphs. She needs it for entrance into Nying Market, a dangerous goblin black market, to find a remedy for the nightmares plaguing her since the spell concealing her identity was broken. Graves appears uninvited, helps her steal the bracelet by posing as her husband, and reveals his true purpose: He wants Kierse to steal the Cauldron of Dagda, another of the four Celtic objects, from a mysterious figure known only as the Curator.

Their first lead is Estelle Beaumont, the warlock of Paris, who tests Kierse with a riddle game and reveals the cauldron will be auctioned. Estelle warns that Graves is using Kierse as a pawn. That night, Graves reads Kierse's drained mind and identifies her nightmare as a resurfacing memory of a young Kierse hidden under floorboards while screams echo around her. He theorizes that the spell also wiped her childhood memories, which are now returning.

Back in Dublin, Kierse discovers her neighbor Niamh is the "robin," a designated agent of Lorcan, the Oak King and head of the Druids, in a centuries-old seasonal magical conflict with Graves, the Holly King. Niamh admits Lorcan sent her to spy but insists she stopped reporting and has been secretly training Kierse and Gen in magic.

Kierse, Graves, and Niamh enter Nying Market, a grim underground bazaar run by goblins who sustain themselves on goblin fruit, an addictive substance. They survive violent encounters and locate memory potions, though Kierse must reveal she is a wisp to obtain them.

Kierse takes the potions with Graves as her anchor. The memory reveals her parents alive: her father Adair and her mother Shannon, a wisp who did not die in childbirth as Kierse believed. They were hunted by someone called "the Fae Killer." The memory shifts to Graves's brownstone twenty years earlier, where her parents sought help. Graves gave them the name of Cillian Ryan, a rogue Druid who could cast a concealment spell.

Returning to New York, Kierse and Graves negotiate a deal: her help stealing the cauldron in exchange for his help recovering her memories. He assembles a team including treasure hunter Lazarus "Laz" Kates; Augustin "Schwartz" Saint-Fleur, a Haitian mer (a sea-dwelling magical being) working undercover on the Curator's security detail; and Nate, a werewolf alpha and one of Kierse's closest friends. The cauldron will be showcased at Monster Con at the Plaza Hotel.

In Brooklyn, Kierse reunites with Ethan, another close friend now training as a Druid, who warns that Graves cannot be trusted. Lorcan reveals his wife Saoirse was a wisp killed by the Fae Killer and offers Kierse a home among the Druids, access to the Oak Throne (the living seat of Druid power), and knowledge of wisps. He reveals he was part of the last triskel, a powerful three-person bond between a wisp, High Priestess, and Druid. Kierse declines.

Memory work yields breakthroughs but also barriers. Every time Kierse approaches the Tribeca apartment where Cillian Ryan cast the spell, the memory skips and she bleeds from the resistance. A psychiatrist at the Covenant, a monster hospital, identifies two blocks: one magical and one psychological, the latter shielding her from the trauma of her parents' deaths.

At a midnight auction, Imani, Graves's ex-apprentice and the warlock of Chicago, disrupts the event by dosing the crowd with wish powder, a substance that amplifies desire. Under its influence, Lorcan declares Kierse his soulmate. The intelligence gathered confirms the cauldron will be on full display at Monster Con, providing the window the team needs.

Kierse agrees to triskel training in Brooklyn to strengthen her abilities before the heist. During the session, Ethan accidentally drains all her magic and she collapses. By the Oak Throne, Lorcan kisses her, and their combined magic nearly triggers a binding. Kierse uses a mental technique Graves taught her to pull away.

She tells Graves about the kiss. He gives her the knife her father traded in his library twenty years ago and reveals the truth about Lorcan's sister Emilie: Graves attempted to break Emilie's soulmate bond at her request but pushed too far, destroying her mind. Kierse tells Graves she loves him, and he says it back. In a final memory session, she breaks through the psychological block and witnesses the Fae Killer shooting her parents while young Kierse hides.

The Monster Con heist unfolds on the summer solstice. Gregory Amberdash, Kierse's former employer, is revealed as head of the Men of Valor, a faction opposed to the Monster Treaty governing coexistence between humans and monsters. Gen is wounded disabling the security system but succeeds. Kierse swaps the cauldron for a decoy, and Laz carries it out. As Kierse exits, a cultist chloroforms her.

She wakes bound with iron and discovers the Curator is Jason, her former thieving mentor she believed dead. Jason is Cillian Ryan. The spell he cast was never a concealment but a siphon continuously draining Kierse's magic and feeding it to him. Kierse phases out of the iron chair using a wisp ability, blasts the guards, and is shot through the shoulder. Jason escapes, warning that the Fae Killer is still active and Kierse already knows the killer's identity. Following his escape, Kierse tracks the cauldron's signal alone into Nying Market, where she discovers Sansara, a hidden compound housing a supposedly destroyed sacred Druid tree, before being recognized and fleeing.

Depleted and bleeding, Kierse calls through the soulmate bond to Lorcan, who rescues her but forces a binding ceremony in the Oak Throne room, tying their wrists with golden thread while claiming Graves has been corrupting her mind. Niamh refuses to continue and challenges for the throne.

Graves bursts through the doors with the Spear of Lugh, accompanied by Gen and Ethan, who came to Graves after learning of Lorcan's plan. Graves cuts the binding threads, but Lorcan warns the ceremony is complete: He now controls Kierse's magic, and killing him would kill her. The solstice weakens Lorcan, and Niamh claims the throne, exiling him.

When Kierse holds the cauldron, it cannot break the binding but fills the half of her magic she never had as a half-human wisp, granting new powers Lorcan cannot control. Graves reveals the cauldron refused his own request to restore Druidic magic he lost decades ago.

At Nate and his fiancée Maura's wedding, Men of Valor operatives led by Nova Lee storm the ceremony. Kierse's new powers fail when she tries to save Nate, and Nova rips out his throat. Maura cradles his body, screaming that he must survive for their baby, the cauldron's infertility cure having already worked.

In a closing interlude, Lorcan operates from exile, calling Oisín, the immortal intermediary between himself and Graves, to declare his intent to pursue the Stone of Fal, the last unclaimed of the four Celtic objects. Three are now in play: Graves holds the spear and cauldron, while Lorcan has the sword. A second monster war is rising.