"Manhole" is a psychological horror manga written and illustrated by Tetsuya Tsutsui. The story is set in a small, isolated town where a mysterious and deadly virus begins to spread, turning infected individuals into violent, zombie-like creatures. The narrative centers around Shun, a young man who works as a civil engineer and is tasked with maintaining the town's sewer system. Shun's mundane life takes a drastic turn when he discovers that the virus originates from the sewers, and he becomes one of the few people aware of the true source of the outbreak.

As the infection spreads rapidly, the town descends into chaos. Shun, along with a small group of survivors, including his childhood friend Rika and a local doctor named Dr. Kurosawa, must navigate the perilous environment to find a way to stop the virus. The group faces numerous challenges, including the infected townspeople, the collapse of social order, and the psychological toll of their dire situation. Shun's knowledge of the sewer system becomes crucial as the survivors attempt to find a safe route out of the town and uncover the truth behind the virus.

The manga delves into themes of survival, human nature under extreme stress, and the consequences of societal breakdown. The characters are forced to make difficult moral decisions, often questioning their own humanity in the process. Shun's transformation from an ordinary worker to a reluctant leader is a key element of the story, highlighting the impact of the crisis on individual identity and relationships.

"Manhole" is noted for its intense pacing, graphic depictions of violence, and exploration of the darker aspects of human behavior. The narrative maintains a sense of urgency and tension throughout, keeping readers engaged with its unpredictable twists and turns. The manga's conclusion ties together the various threads of the story, providing a resolution to the characters' struggles while leaving room for reflection on the broader implications of the events depicted.