Manhole is a Japanese horror manga about a manhole cover that mysteriously vanishes, exposing a vast, dark underground network teeming with grotesque, parasitic creatures. The story follows a police officer and a young boy as they descend into the tunnels to rescue people and uncover the source of the nightmare. Readers enjoy it for its claustrophobic, relentless tension, visceral body horror, and the suspenseful, survival-driven exploration of a decaying, alien underworld.