Instructions
Travel to Rock Tunnel. Battle your way to Rocket Game Corner.
Confront Giovanni and engage him in battle. Water attacks work well against his buddies, Onix and Rhyhorn. Watch out for Kangaskhan's special attacks. Your party should be equipped to handle the battle without much difficulty, but if this is not the case, spend some time gaining a few more levels.
Exit the rock Tunnel. Use an escape rope if you have one to shorten the trip. Walk south and cut down the tree. Follow the trail to the gym where a peeping tom lurks outside, watching the women workout.
Enter the Celedon City Gym and interrupt the girls' workout. Defeat all seven trainers, preferably with the help of fire-based Pokemon such as Flareon, Ninetales and Arcanine.
Take the fight to Erica, using fire- and flying-type abilities whenever possible. Use psychic abilities on Vileplume. Use Awakening and Paralyze Heal when afflicted with relevant status effects. Bring Erica down to earn your fourth badge.