Tunnels

The story opens in the London borough of Highfield, where fourteen-year-old Will Burrows and his father, Dr. Burrows, share a secret passion for underground excavation. Together they discover a sealed Victorian train station, abandoned since 1895. Dr. Burrows, the curator of the neglected Highfield Museum, swears Will to secrecy. Their clandestine digging is the primary bond between father and son.

Will's home life is dysfunctional. His mother, Mrs. Burrows, spends her days immobile before the television, while his twelve-year-old sister, Rebecca, slim and dark-haired and strikingly different from the pale, white-haired Will, runs the household. Dr. Burrows grows preoccupied with strange observations: pale, heavyset men in flat caps and dark glasses whom he calls "men-in-hats" and whom no one else notices; a small globe in a metal cage, brought to the museum by a visitor, that glows brighter in darkness; and mysterious bottomless ventilation ducts behind chimneys in Martineau Square, named for Sir Gabriel Martineau, a seventeenth-century inventor whose laborers reportedly dug tunnels beneath Highfield.

Will recruits Chester Rawls, a fellow outcast from school, to help excavate a stretch of wasteland called the Forty Pits. They break through a brick wall into an octagonal chamber inscribed with names, where they experience sudden nausea and pressure. When they return, the tunnel has been deliberately sealed with geologically inconsistent infill, suggesting someone blocked their way.

After a violent argument with Mrs. Burrows, Dr. Burrows vanishes, his hard hat and overalls missing from the cellar. Will and Chester break into the museum and find his secret journal documenting research into the men-in-hats, the glowing sphere, and Martineau's history. The final entry declares: "I will be remembered!" (102).

Chased through Highfield by two men-in-hats, the boys barely escape. They discover a hidden passage behind a bookshelf in the Burrows cellar, deliberately collapsed. Over weeks of excavation, they clear the tunnel and break into a grotto containing stalactites, the remains of a rusted machine, and an eyeless white rat. At the far end, a heavy iron door opens into an air-lock chamber.

Beyond the air lock, they descend via a cage elevator into a vast subterranean cavern. A cobblestoned street stretches before them, lit by large versions of the glowing spheres and lined with inhabited houses carved into the rock. They explore an unlocked house and find warm tea, a furnished parlor, and portraits resembling the men who chased them. A massive uniformed policeman seizes them, saying Will's father told them the boys would come.

Will and Chester are locked in a cell and interrogated by the Styx, tall, gaunt figures in leather coats with jet-black eyes who govern the underground settlement. The Styx use a device called the Dark Light, a lamp whose pulsing energy induces disorientation and unconsciousness, leaving both boys unsure what they revealed. Afterward, Mr. Jerome, Will's biological father and a hostile man, and his young son Cal visit Will. Cal tells Will his real name is Seth, that they are brothers, and that their mother fled to the surface with infant Will but was forced to leave Cal behind. Will rejects the claim.

Released from detention, Will is taken past the Skull Gate into the Colony, a network of enormous caverns housing an entire underground civilization. At the Jerome house, Grandma Macaulay, Will's maternal grandmother, shows him a photograph of a young white-haired woman holding a baby, identifying the woman as Sarah, Will's real mother. Despite his suspicion, Will feels certain she is telling the truth and begins to accept that the Burrows family were not his biological relations.

Uncle Tam, Will's maternal uncle, confirms that Dr. Burrows passed through the Colony and departed on the Miners' Train for the Deeps, a network of tunnels far below. Will settles uneasily into Colony life, attending mandatory church services and enduring work details. He discovers that the serving man in the Jerome household is Terry Watkins, a demolition worker whose family was abducted after he stumbled upon one of the Colony's access points.

Will begs Tam for help rescuing Chester. Tam warns that escaping will make Will a permanent fugitive but agrees, providing a cloth map through the Labyrinth, a vast tunnel network, and four node stones, rare objects that produce blinding light when cracked open. Will sneaks into the police station, blinds the officer with a camera flash, and frees Chester. They flee to a rendezvous point, but the Styx ambush them. Cal and Bartleby, the Jerome household's enormous hairless cat, have followed Will.

Rebecca steps from among the Styx wearing their black coat and white collar. She reveals herself as a Styx planted in the Burrows family at age two to monitor Will and potentially flush his real mother into the open. Will hurls a node stone, its flash incapacitating the Styx, and Cal slips through an airtight door leading toward the Eternal City, an ancient abandoned underground metropolis. The Styx seize Chester, and as the massive iron door descends, Will must release his friend or watch him be crushed. Chester is pulled back, and the door slams shut.

Will, Cal, and Bartleby flee through the Labyrinth toward the Eternal City, Will growing increasingly ill. The cavern is lit by bioluminescent algae and filled with the ruins of the ancient metropolis. A dense fog rolls in, and Will uses fireworks to create diversions against pursuing Styx patrols. A stalker dog attacks Will before Bartleby drives it off, though the cat does not rejoin them.

Tam and his associate Imago Freebone find the boys, but at the Labyrinth entrance, the Crawfly, a Styx who has pursued Will's maternal family for years, confronts them with an army. In a brutal fight, Tam kills the Crawfly but is mortally wounded. He gives Will a jade pendant, makes him promise to protect Cal, and turns alone to face the advancing Styx.

In a hidden chamber, Imago tends Will's wounds and gives him water-damaged fragments of Dr. Burrows's journal, confirming his father thought of him during his journey. Will and Cal choose to descend into the Deeps rather than return to the surface, resolving to find Dr. Burrows. Imago times their departure to the Miners' Train, and they drop onto the moving cars. Will discovers Chester huddled in a rear car, sentenced to Banishment and transported to the Deeps, exactly as Imago planned. Reunited, the boys share a moment of relief as the train carries them deeper into the earth.

Far below, Dr. Burrows camps alone beside a circle of carved stones, sketching unknown symbols by firelight. He is consumed by discovery yet aching with loneliness, muttering, "I have to do this" (315).

In an epilogue, Imago, living under an alias at a London pub, is poisoned by an undetectable compound. Across the street, a girl shakes out jet-black hair and walks away singing. It is Rebecca, confirming that the Styx have begun their revenge.