Gotta Catch ‘Em All
In the last part of our Pokemon HeartGold walkthrough you chose a starter Pokemon and retrieved the Mysterious Egg from Mr. Pokemon. Now you're ready to start your journey for real. Being a Pokemon trainer in Johto means collecting all eight badges and challenging the Elite Four to take on the role of Pokemon League Champion–but you've got a long way to go.
For now, head west out of New Bark Town to meet your friend from earlier. She and her Marrill will give you a Pokemon capturing demonstration and five Poke Balls, meaning you can finally capture Pokemon and expand your team–a necessity if you plan on taking on the Violet City gym leader, Falkner.
Continue west as if you were heading to Cherrygrove City, but this time head up to the building to the north and go through to reach Route 46. Here you can catch the rock-type Pokemon Geodude which will be a formidable ally against Falkner's bird-type Pokemon.
Reaching Violet City
Continue along to Cherrygrove City and once again head north up Route 30. You'll find a few trainers to battle here, so take them on to earn money and experience points, and continue up to where you visited Mr. Pokemon in the last part of our Pokemon HeartGold walkthrough.
This time, continue past Mr. Pokemon's house and north to Route 31. Route 31 has another triad of trainers to face, but none of them should give your growing Pokemon party too much trouble. At the end of the route you'll pass through a building into Violet City. Along the way your friend will show up to give you the Vs. Recorder, which lets you keep a record of all your Pokemon battles and even record specific matches so you can send them to friends over the Nintendo Wi-Fi Connection. Continue through this building and you'll find yourself in the small town of Violet City. Apart from the Pokemon Center and Poke Mart, you'll see a new fixture of most important towns in the Pokemon universe–the town's Pokemon Gym. Before you can enter, though, you'll need to complete a separate challenge at the Sprout Tower.
The Sprout Tower
You won't have to look far to find the Sprout Tower. This tall, purple-roofed building sticks out of the middle of the town. Just cross the small bridge at the town's north end to reach it. There's not much to do on the tower's ground floor, so take the ladder up to begin your challenge. All told, you'll have to battle seven monks and their Pokemon–a combination of Bellsprout and Hoothoot. The Pokemon range in level from level 3 to level 10, getting progressively harder as you go along. This gives you a good chance to gain valuable experience points before the main event, your battle against Falkner.
Before you battle the final monk, you'll spot your red-haired Rival in the tower as he's just finished completing the challenge for himself. You won't get to battle him this time since he runs off before you can confront him, but at least you now know that he's always just one step ahead of you. Defeating the final monk earns you TM70: Flash which will be required for exploration of certain areas later on.
Pokemon Gym Leader Falkner
Now you're ready to take on your first Pokemon Gym Leader, Falkner. Falkner uses Pokemon of the bird variety. Before you battle Falkner himself, you'll need to take on his two underlings. They shouldn't be too hard to deal with. With them out of the way, it's time to battle Falkner. He has a level 9 pidgey and a level 13 Pidgeotto, so you'll want your Pokemon to be in that same level range. If you caught a Geodude earlier, it will learn the move rock throw at level 11–use this attack to easily dispose of Falkner's flying-type Pokemon. Note that if you picked Chikorita as your starter Pokemon, you'll be at a slight disadvantage since flying-type attacks do extra damage to grass-type Pokemon.
Defeating Falkner earns you the Zephyr Badge, which lets you control Pokemon up to level 20 and use the moves flash and rock smash outside of battle. He'll also give you TM51: Roost, a restorative move you can teach to a flying-type Pokemon.