In a world resembling our own, a secret game called Rabbits has been running beneath everyday life since at least 1959. Players advance by identifying patterns, discrepancies, and coincidences in the real world, from altered paintings to anomalies in old video games. The game operates in numbered iterations, each ending when a winner is declared on a mysterious list called The Circle. Participation is shrouded in secrecy and carries rumors of physical danger and death.
K, the narrator, is a pattern-obsessed Seattleite who hosts informal sessions about Rabbits at an arcade run by a figure known as the Magician, the arcade's enigmatic owner who once played the game and now advises others. K has an unusual gift for recognizing patterns, accompanied by a condition K calls "the gray feeling": episodes of buzzing, tingling, and encroaching darkness, as though something vast is pressing in from beyond the world. K's obsession traces to a childhood Fourth of July party, where K overheard Emily Connors, the older daughter of family friends, describing a secret game. That night, Emily drove K and Emily's younger sister Annie up a dark road, turned off the headlights, and tuned the radio to a specific frequency. Through the static, K heard a woman's voice say, "The door is open." The truck struck something in the road. Annie died instantly. The trauma became the foundation of K's lifelong obsession. K's parents later died in a ferry accident, leaving K alone at seventeen. A period of intense grief and obsessive pattern-following led to a mental health crisis and hospitalization. K eventually found community at the Magician's arcade, meeting Chloe, a former musician who works there, and Baron Corduroy, a quick-witted former stockbroker turned coder.
The central action begins when Alan Scarpio, a reclusive billionaire believed to be the winner of Rabbits' sixth iteration, appears at the arcade. He tells K something is wrong with the game and asks for help, warning that otherwise everyone is "well and truly fucked." Scarpio plays K a recording of rhubarb growing, then receives a disturbing phone call and vanishes. Days later, he is publicly reported missing. K retrieves Scarpio's phone, left behind at a diner. The Magician traces the call to WorGames, a major videogame company founded by the reclusive Hawk Worricker. K and Chloe discover the phone contains a hidden video depicting an attempted murder that never occurred in real life, the kind of impossible discrepancy that signals the game is active.
K also begins losing hours of time and remembering a film that apparently does not exist. Baron takes a job at WorGames playtesting a game built on the Byzantine Game Engine (BGE), a proprietary system producing virtual reality indistinguishable from real life. A tester dies during a session, and Baron witnesses the incident. K and Chloe later find Baron dazed and surrounded by chaotic notes; the next morning, he is dead of cardiorespiratory collapse. On an old computer in a Georgetown building, K and Chloe discover a live feed of a British politician shooting himself after declaring "The door is open." The Circle displays Roman numeral XI: The eleventh iteration has begun.
Game designer Sidney Farrow, who oversaw Baron's project at WorGames, arrives at the arcade seeking information about his death. She reveals that a restricted building called The Tower houses the BGE. During a visit to WorGames, K is pulled by an unseen force into an elevator that ascends to The Tower's penthouse. There K meets Crow, a man who claims to have known K's parents and who presides over a massive surveillance operation. Crow describes the Meechum Radiants, theoretical lines of energy beneath the world. Emily Connors appears briefly, shocked to see K. When K returns minutes later with companions, the penthouse has transformed into rows of servers, and Crow's lair is gone.
Warnings multiply. The Magician tells K and Chloe that players worldwide are disappearing and dying. A reclusive surveillance operative called Fatman Neil, who maintains a citywide monitoring network, confirms the pattern. A mysterious woman named Swan, who claims to be working for Scarpio, arrives with identical twins; she takes Scarpio's phone and warns that time is running out. On a bus, Crow threatens K directly: If K continues playing, everyone K knows will forget K exists. K records the encounter. When K shares everything with Chloe, she reveals she has no memory of meeting Sidney or visiting WorGames.
Emily Connors picks K up at a monorail station that should not exist and takes K to an alternate-dimension lakeside mansion. Emily explains that Worricker created Rabbits to stabilize a decaying multiversal repair system connected to the Meechum Radiants. Crow lost his daughter Natalie to a dimensional accident and has been manipulating the Radiants to find her, destabilizing the game and threatening the multiverse. Emily tells K she intends to kill Crow.
K and Chloe find Fatman Neil murdered, his network dismantled. A chain of clues, including an unreleased Steely Dan recording and a novel called
The Horns of Terzos, leads K to a fantasy map that overlays onto Seattle, with three points forming a triangle and a labyrinth at the center corresponding to The Tower. K and Chloe follow this map as reality deteriorates: shadow creatures gather, ravens erupt from trees, and the gray feeling intensifies. At a coffee shop, Chloe vanishes from the bathroom. K discovers that Chloe's name is gone from her apartment directory, and a stranger claims to have always lived in her unit. K presses on alone and passes out after shadow creatures pursue K into a freight elevator.
K wakes in The Tower's penthouse. Emily reveals that in another dimension, she and K are married. K crossed between parallel realities, or dimensional streams, four years ago to stop Crow, but the transition caused memory loss that erased K's knowledge of their shared life. Emily explains that their parents were part of the Gatewick Institute, where a prenatal drug study gave certain children, including K and Emily, the ability to manipulate the Meechum Radiants during extreme emotional distress, the source of K's gray feeling. When they confront Crow, he insists the dimensional stream is resetting to restore his family. Swan and the twins arrive and kill Crow, then deliver grim news: The Radiants have fallen too far out of alignment, and all connected dimensional streams will collapse. Swan estimates roughly an hour before the end of everything.
Emily corrects K's memory of the childhood accident: it was an unlit tractor in the road, and it was K who turned the wheel, saving Emily but unable to save Annie. K convinces Emily to drive to the same road. They tune the radio to frequency 107.3, turn off the headlights, and drive into the darkness, recreating that night's conditions. K enters the in-between place—a dark liminal state of floating and currents that K experienced since childhood—reaches into the darkness, and makes a choice. The world explodes in light and fire.
K awakens in a house where Scarpio has been waiting after receiving a mysterious postcard. Scarpio explains that Rabbits is powered by an advanced artificial intelligence running on a quantum computing system Worricker created decades ahead of its time and suggests the game orchestrated everything K experienced. The Circle appears on the Tokyo Stock Exchange ticker, listing K as the winner of the eleventh iteration. Chloe arrives, alive and well. The Magician is also alive, though Baron and Fatman Neil remain dead. K and Chloe sit down to eat French toast, ready to wait for the next iteration to begin.