In the quiet, dying town of Harrow's End, something has awakened beneath the cracked streets and rotting houses. At first, it's small things—missing pets, strange scratching sounds in the walls, and the smell of rot wafting through basements. But soon, people begin to vanish, their homes left streaked with a black, tar-like slime that no one can explain.

A group of residents—an out-of-work miner, a schoolteacher, and a grieving mother—discover that beneath Harrow's End runs a forgotten network of tunnels from an abandoned coal mine sealed off decades ago after a cave-in. But the collapse didn't just bury men; it buried something far older. Something that has been waiting.

The creature doesn't strike fast—it crawls, dragging itself slowly, relentlessly, through pipes, under floorboards, across ceilings, and through the dark corners where no light ever reaches. You never hear it coming until it's too late.

The survivors realize that the more it feeds, the bigger it becomes—splitting, multiplying, and spreading like a disease. Soon, it isn't just in the tunnels. It's in their homes, their schools, their very walls. The town becomes a trap where every creak, every drip, every shadow might be the sound of it crawling closer.