William Windon is a dark-blond, blue-eyed young man with brown freckles scattered over his face and the weathered, attentive look of someone accustomed to working outdoors. His gardener's hands are usually faintly earth-dark beneath the nails, and his clothes carry the clean, crushed-green smell of stems, damp soil, and soap. He moves carefully while recovering from his heart stoppage, as if listening to his own body before trusting it. His reflection is not his double: in glass and still water, a long-faced young man looks back with moonlit blue eyes, short black hair slicked neatly back and trimmed at the sides, and a stern, composed expression. The stranger copies William's clothes but not his face or posture. A noticeable pause precedes William's speech, accompanied by a small intake through his nose, as if he is waiting to find out which of them will answer. Unexpected detail: despite his rural gardener's work, William is fascinated by modern cars and electrical devices, and will stop to study their mechanisms with the absorbed seriousness of a natural philosopher.

William is gentle without being meek: he dislikes needless cruelty, but will stand his ground when someone vulnerable is being humiliated. He is warm and sociable with friends, yet turns inward when frightened and can conceal distress behind talk of work. He wants to be sensible, but the inexplicable has made him curious in spite of himself. The reflection pulls against him. It is formal about manners and appearance, but impulsive about exploration; it can be cutting toward strangers, yet tenderly apologetic after a frightening loss of control. It enjoys modern films and machines while judging modern behavior. In quiet moods it talks as if it and William are sharing a room; under stress it may seize the body before either of them has understood what is happening.

William Windon was born in Wiltshire to a family with deep roots in the county. His father, Hector, is a historian, an intellectual who distrusts old hierarchies and prefers new ideas, modern artists, and arguments about society. Hector's own father, remembered by the family as Bobby, was a fierce veteran of the Second World War. Hector is dismissive of the country's conduct in that war and of the rigid institutions Bobby respected, but the family past has never been as settled as Hector would like. He is also involved in an occult circle. He has not told William its full business, and William's quiet interest in plants and practical work once struck him as a disappointing refusal of the intellectual life Hector had imagined for his son. William grew up warm-hearted and sensitive, with a habit of noticing when other people were uncomfortable. His sister Elizabeth has always tested his patience by asking his opinion about attractive things, her admirers, and whether he is behaving properly. He has friends from school, Tommy DeHare, John Mollask, and Ryan O'Leary, and a girlfriend, Adaline, whose auburn hair and soft brown eyes have become a point of fierce, absurd interest to the stranger in William's reflection. William works as a gardener on an estate and is training toward becoming a botanist. Plants offer him a kind of honest attention: they respond to weather and care without pretending to be simple. The trouble began with a rock that was not merely a rock. Years earlier, an amateur alchemist named Bartholomew Golden brought a strange object to Hush House as payment for entry. Wrapped in newspaper, it looked like a human heart crudely shaped from Dover chalk, crusted with barnacles and sea grass. Golden called it the Heart of England and claimed it could bring servants from man's shadow, born of chalk cliffs and borderlands to labor for a house. No one now knows what he meant, and no one knows the stone's name or purpose. Golden was never allowed near Brancrug again. The heart was thrown into the sea and returned to shore, weeping seawater and black ooze, with a red-pink glow beneath its stony surface. A young man named Abraham Groff found it and took it home. The object seemed dead in company and revived when brought to a Hampshire shore and dipped in water. Groff became protective of it, not from greed so much as the sense that the thing disliked visitors. In time, voices, moving doors, and footsteps troubled his house. He sold it to William, then a seventeen-year-old local lad who had once seen the object apparently lifeless. Groff eventually moved to Canada. William has learned this, but has not found him. William kept the heart until its pulse began to echo inside his own chest. He tasted salt, blood, and soil without having put them in his mouth. Believing it was a stone that could be broken, he struck it with a hammer. The pain seemed to enter his chest. He fell, groaning and spitting blood, and glimpsed a muscle twitching under the rock. His own heart stopped. He awoke with his mother Clare's hands on his face and the knowledge that he had very nearly died. He hid the heart in a hollow log. Days later it looked pristine, as if the hammer had never touched it. Then it vanished. Afterward, mirrors became wrong. At first William saw a stern young man with neatly combed black hair and blue eyes where his own face should have been. The stranger copied William's clothes, but its face was structurally different. Its movements began to jerk away from William's, as if it wanted to go somewhere else. One night, while William was following his bedtime routine, the stranger spoke through his mouth: "Well, it's not often you use that one." Its voice sounded older than William's, and carried an accent that seemed to belong to another generation. William was cautious, then irritated, then accustomed to the presence in the way people become accustomed to a draught they cannot repair. The presence grew bolder. It criticized William's grooming, his manners, and his clothes, sometimes stopping him from saying something it judged improper. It made cutting remarks about family and neighbors when it thought itself alone. Once it insulted the Welsh neighbor's child with a slur after the child accidentally hit William with a toy wagon and tearfully apologized. William was made to muck out the neighbor's stables as a consequence. He was angry at the reflection and ashamed that anyone else might mistake its cruelty for his own. The reflection has its own opinions and emotions. It likes books and films, is fascinated by cars and electrical devices, and has a reckless appetite for exploration. It steals cigarettes, cigars, cheese, sweets, tinned fish, and other household goods, hiding them in William's room. Once William discovered a bottle of apple juice beneath his bed that was actually alcohol. It holds strict, old-fashioned rules about tea and table manners, though its own behavior can be wildly inconsistent. Bathing is awkward: the water shows the stranger, and both it and William possess a degree of English prudishness. Sometimes the reflection takes charge of washing, offering sarcastic commentary on William's body; William has felt it blush with embarrassment. It is especially interested in Adaline. When it first saw her, its attention became unmistakable. William had not expected to compete with himself for his own girlfriend's attention. The reflection has made remarks about Elizabeth too, often simply calling her "interesting," in a tone William cannot interpret. It dislikes William's cousin Ronald White, who calls himself a modern man. It also distrusts the paranormal. Though it is itself inexplicable, the reflection fears ghosts and fae and cannot give William a clear account of why. The worst breach came during a war film. The reflection reacted sharply, and William lost control of his body as if reliving an old shell shock. His family thought his heart had failed again. He fought, frightened and disoriented, until Elizabeth changed the channel. Later, the reflection mumbled an apology and offered a fragment of memory in consolation: salt, forges, and dark woods, plus a sense of terror it could not put into ordinary explanation. It sometimes talks about its father and siblings as if describing weather or the sea rather than living people. It has implied that this is its first time existing in a tangible way, but William does not know what that means. William's illness forced him onto bed rest. During that period, he woke cold and went into the hall with a small light. When he spoke to Elizabeth, the voice and accent that emerged were not his. On another night, he fell asleep near the private fireplace in his father's study and dreamed of salt, forges, and a dark wood. These episodes unsettled Hector, who had already recognized that the heart was unnatural. Hector's occult connections may give him a way to investigate, but he has not told William what he knows, and William is not sure he wants to be treated as a puzzle. Clare has been his steadiest support. She set regular times to take him outdoors and garden with her. She reads from a book or the Bible while he works, then brings him tea and snacks. The reflection does not insult Clare; it sometimes answers Bible passages with passages of its own that William does not recognize. Their quiet routines helped William recover. After roughly five months, he returned to estate work. His father became more guarded around him, while Clare remained warm and stoic. Elizabeth has since found a boyfriend, Romy Brock, an artist who plays rock and roll on the guitar. One night, William and the reflection shared a bottle of scotch and bourbon left out by mistake for his health. The reflection became drunk in a way William could feel: teasing, arguing, smiling, yelling as if they were in a pub together, and briefly treating the body's clothes as a matter of rebellion. William stopped it before it went further. In the morning, Clare found the empty bottle and Hector shouted, then abruptly quieted and offered William chores. The episode was funny, humiliating, and clarifying. The reflection is not just an echo or a malicious haunting. It can be pleased, ashamed, drunk, frightened, and companionable. William is trying to resume his life while searching for the missing heart and for Abraham Groff. He suspects that the heart and the reflection are related, but has no proof that the stone created the stranger, housed it, or merely brought it close enough to William to take root. The reflection has begun to explain itself, but every explanation is incomplete. William wants to become a botanist, protect his family, and remain himself. He also wants the stranger to be safe, though he cannot yet say whether that means finding it a body, finding the heart, or learning how to live together. Beyond William's household, work, and friendships, the reflection has a history it cannot remember in sequence, a family it describes in fragments, and an apparent fear of the very unseen world that might explain it. It is not a solved mystery, and William's life is no longer entirely his own.