For Lieutenant Wilson Jericho, Hell is real: and it's in the sewers of the sprawling city Megalopol, where, as an officer of the Sewer Police, he's responsible for ensuring the bowels of the city run smoothly. He knows everything there is to know about the underworld, which is why he's chosen to serve as tour guide for Sandra Yeatman, a young scientist who aims to prove the truth of legends about the strange wildlife in the sewers.