With the fourth badge in hand, Joshua & Mr. Squirt turn their attention to Celadon City's seedy underbelly and purge the Game Corner of Team Rocket, for which they receive the extremely niche yet "premium" product, Silph Scope. They return to Lavender Town to free Mr. Fuji and some Pokémon souls before embarking on Routes 12-15 to cool their heels down south for a while. Once in Fuchsia City, they go on safari, find some gross Gold Teeth, and defeat Koga, the fifth Gym Leader.