From the Super Mario Wiki, the Mario encyclopedia
The chapter takes place in a giant factory structure underneath (and partly in) the town of Chapter 4. As implied by the name this chapter is largely composed of factory-themed levels where the player has to avoid dangerous machines and deal with distracting conveyor belts. At the end of the chapter, Wario battles Captain Syrup in one of her various crafts.
List of stories
Sub-bosses and bosses
Names in other languages