The Sewers is a large area accessible from the Nexus, and connects to the Dark Alley, the Mall, the Barracks Settlement and the Block World as well. It resembles The Sewers from the original game. A few Pirori, a Ghost and the Black Cat can be found here. There is also a room full of Alley Demons, which can be accessed by freezing the water with the Scarf and Hat/Umbrella effect combination, and requires the Mask of Fear to get through as well.

Making the Cat run away causes it to appear on The Mall's rooftop, along with the Mysterious Cartridge.