Ghosts of Greenglass House

The story follows twelve-year-old Milo Pine, a Chinese adoptee living with his white parents at Greenglass House, a hilltop inn overlooking the Skidwrack River in the fictional city of Nagspeake. As winter vacation begins, Milo is upset about more than the disappointing frost on the lawn. His social studies teacher, Mr. Chancelor, has twice humiliated him in class: first by dismissing Milo's accurate claim that a Chinese-British family built Greenglass House before the War of 1812, and then by asking Milo to translate Chinese characters in front of his classmates simply because he is Chinese. Milo, who is learning Mandarin with his parents but is not a native speaker, could not read the older writing system, and the experience left him feeling as though he does not qualify as an "actual Chinese person." His father gently encourages Milo to let his parents intervene, and Milo tentatively agrees.

The inn's sole guest is Emmett Syebuck, a young art student fascinated by the house's stained glass. Milo craves a quiet family Christmas, but the previous year, unexpected guests led him to discover Odd Trails, a role-playing game through which he created Negret, a trickster-thief alter ego who helped him solve mysteries at the inn alongside Meddy, the ghost of Addie Whitcher, daughter of famous smuggler Doc Holystone. Meddy has been absent for a full year, and Milo misses her desperately.

Two familiar faces arrive via Nagspeake's secret underground transit system: Clem Candler and Georgie Moselle, young thieves who became friends of the family the previous year. Clem is now engaged to a man named Owen, and their cover story is a bachelorette weekend. In truth, they have just pulled a heist involving a hidden cache belonging to Violet Cross, one of Nagspeake's most legendary smugglers, discovered beneath the warehouse of Toby Gilawfer, a fence who granted them access. The main prize, a derrotero (a secret book of navigational charts for the supposedly unmappable Skidwrack River), was not among the recovered items, which included ten locks, eleven unusual keys, and several other objects. They suspect Gilawfer of planning to betray them and fear a mysterious master thief called Cantlebone may be pursuing them. The Pines assure them they are welcome to hide at the inn.

The household's fragile peace shatters when seven traditional carolers called the Waits arrive from the nearby Liberty of Gamverbund, a walled community within Nagspeake that outsiders dismissively call a madhouse but that is actually a sanctuary for those seeking asylum. The group includes Peter Hakelbarend, the huntsman-clad leader; Lucky, a young woman devoted to the tradition; Rob Gandreider, a chimney sweep; Barbara Kirkegrim; Nicholas Larven, a dapper older man; Sylvester Alforn, a bell-covered dancer; and Marzana, a withdrawn teenage girl who operates a terrifying hobby horse, a grinning skull with candle-lit eye sockets and stag antlers.

Chaos erupts. Rob's chimney cleaning fills the house with soot. While Milo leads Marzana and Mrs. Kirkegrim upstairs, both are struck by an unseen assailant. Mr. Larven collapses from apparently poisoned punch, and Clem kicks a cup from Mrs. Pine's hand before she can drink. Overwhelmed, Milo goes outside and encounters a figure dressed as Doc Holystone at the edge of the woods. The figure identifies himself as Meddy's father, warns that Gilawfer was an informant for the customs department, and suggests the derrotero may not resemble a conventional book. He asks Milo to keep his presence secret.

That night, Meddy finally appears outside Milo's bedroom door. Milo confesses he cannot access his Negret persona, and Meddy diagnoses the problem: its controlled nature does not suit the current chaos. In the attic, they design a new character combining a disciplined, monk-like fighter with an ecstatic who channels overwhelming emotions into power. Milo names this alter ego Téngfēi, Mandarin for "flying," choosing a Chinese name and backstory that feel authentically his. While there, he also finds a red lacquer box containing a white feather and a small gold vial, which he adopts as tools for his new persona. When Milo relays Doc's message, Meddy rushes to the window to wave at her father but cannot see him through the trees that have grown since their last contact. Doc, when Milo finds him outside, is devastated to learn Meddy is so close yet invisible to him.

The next morning, Téngfēi and Sirin (Meddy's scholiast character, a type of spirit familiar in the game) learn all cache items have been stolen from Clem and Georgie's rooms. Deducing the items were hidden back in the victims' own rooms, Téngfēi methodically recovers them from ingenious hiding spots. He also discovers poisonous holly and mistletoe berries in the tea ball used for Mr. Larven's punch, confirming deliberate sabotage.

Owen arrives unexpectedly and shares with Milo his own painful experience as a Chinese adoptee, advising Milo to prepare the words he would use with Mr. Chancelor even if his parents ultimately have the conversation. Owen gives Milo an 1813 letter from Liao Bluecrowne, Owen's ancestor and one of the house's original residents, signed with Chinese characters translating to "the crown that is blue," the origin of the house's original name, Lansdegown. The letter is tangible proof of the Bluecrowne family's Chinese heritage.

Emmett then reveals he is an undercover customs agent sent to investigate the inn but has found no wrongdoing and already planned to clear the Pines. During a storytelling session, Téngfēi retells a Violet Cross story Doc gave him, and Marzana erupts in correction, revealing intimate insider knowledge of Cross's operations. Téngfēi also deduces that Marzana and Peter Hakelbarend are father and daughter, concealing their relationship for safety whenever they leave the Liberty.

Téngfēi and Sirin piece together that at least two criminal operations are working among the Waits. They overhear Rob, Mrs. Kirkegrim, and Mr. Larven arguing: Rob is Gilawfer's team leader, and someone is lying about finding nothing. Rob mentions calling in reinforcements, confirming Gilawfer is nearby. Téngfēi deduces that Mrs. Kirkegrim hid the keys inside stollen loaves before baking, then cranked the oven to burn them; when the ruined loaves were thrown out and the trash dragged to the road, the keys left the house undetected.

Racing outside to recover the keys, Téngfēi realizes Mrs. Kirkegrim is Cantlebone: she infiltrated Gilawfer's team and used their chaos to extract only the keys. The false Doc Holystone, actually Gilawfer in disguise, and De Cary Vinge, a corrupt customs agent, confront them with weapons. Milo begins singing "The Holly and the Ivy," summoning a supernatural golden horse that strikes the gun from Vinge's hand and herds both men off the property. The real ghost of Doc Holystone briefly appears, and Mrs. Kirkegrim recognizes him as an old acquaintance.

Back inside, after Rob is subdued and arrested, Milo reveals his theory: Mrs. Kirkegrim is both Cantlebone and Violet Cross herself. She confirms it. She faked her death thirty years ago when Gilawfer informed on her, escaped with her crew, and has lived in the Liberty with Peter Hakelbarend, her husband and a former customs agent who joined her in asylum. Marzana is their daughter, and Mr. Larven is Violet Cross's trusted lieutenant.

Violet Cross tells Clem and Georgie to keep most of the cache. After the Waits depart, Milo shares a final deduction: the keys themselves are the derrotero. Each key's adjustable teeth correspond to the shifting banks of the Skidwrack's eleven inlets, and the dials in their handles allow recalculation as conditions change. Through two separate maneuvers, Violet Cross got the most valuable item out of the house without anyone realizing what it was. Marzana selects the keys as her keepsake.

Milo then devises a way to reunite Meddy with her father using the game concept of a reliquary, a container that can anchor a spirit to a portable object rather than to the house. He places a figurine inside the gold vial and tucks it in Meddy's pocket. They step off the porch together, and Meddy does not vanish. She walks to the tree line, where the real Doc Holystone appears and waves. Meddy runs into her father's arms for the first time in over thirty years. Doc mouths "Thank you" to Milo over Meddy's head. Milo returns to his parents and lets himself cry, overwhelmed by happiness, sadness, and relief. Snow begins to fall at last, replacing the disappointing frost that opened the story, as the Pine family stands together watching the flakes descend.