After exiting Mt. Moon, you'll be on Route 4. There are a few trainers here, and you can also find a hidden item or two. Continue west to reach Cerulean City. Heal your Pokémon at the Pokémon Center. Before challenging the Gym, you might want to explore the city. There's a Bike Shop, though you can't buy a bike yet. The Gym Leader, Misty, specializes in Water-type Pokémon. Grass and Electric-type moves are super effective. Your Partner Pikachu/Eevee will be very useful here!
