Tunnels Books in Order

When his excavation-loving father vanishes, fourteen-year-old Will Burrows follows the clues underground with his friend Chester. They discover an isolated society controlled by the oppressive Styx, turning their search into a struggle against its rulers.

Still searching for his father, Will ventures beneath the Colony with Chester and Cal. Discovering a Styx plan to unleash a lethal plague on surface dwellers gives their underground journey stakes far beyond their own survival.

Will and Chester plunge through a subterranean shaft while the Rebecca twins pursue them with a deadly virus. A strange fungal landscape offers clues to a lost civilization, while the Styx prepare their attack above ground.

Will explores an inner world with his father and Elliott, studying the mysterious symbols on its temples. Their apparent refuge is threatened when the Rebecca twins return with soldiers determined to pursue him deep underground.

The Styx emerge into London, using human hosts to multiply their population. Will joins a makeshift force of renegades and former soldiers, confronting an invasion whose horrifying biology threatens to overwhelm the world above ground.

As the Styx assault the surface, Will and Elliott retreat underground with a small surviving team. Secrets surrounding three core pyramids may explain the invaders' origins, but finding answers becomes urgent as the planet faces catastrophe.