From Bulbapedia, the community-driven Pokémon encyclopedia.
The Dusk Factory (Japanese: ヨナベこうじょう Yonabe Factory) is an old, abandoned factory in Fall City. It is the location of the seventh numbered mission of Pokémon Ranger. It only operates from dusk until dawn.
The Dusk Factory is in use by the Go-Rock Squad, and the Go-Rock Quads use it for their band practices. Professor Hastings intends to shut down the factory.
This is a listing of the Pokémon found in the Dusk Factory after the credits: