You have to defeat team rocket in the suspicious shop, nw of the guy 1st. Then fly to goldenrod city, and go to the underground. Talk to the rocket grunt, and youll change into a rocket grunt suit. Talk to the rocket grunt blocking your way upstairs in the radio tower, and you have to defeat him, and the rest of them. After that whole process, fly back to mahogany town, and the guy will be gone, then you'll be able to challenge the blackthorn gym.
you have to defeat the other seven gyms to pass to the next city next to mahogany.
To get past you need to have: Beat Team Rocket in Mahogany (Lance found at the Lake of Rage will tell you where the entrance is) Beat Team Rocket in Goldenrod Beat the gym leader of Mahogany, Pyrce.
Well if you're like me always wanting to go ahead if you can't do something and can't wait for it to happen. Well if you are here's what I did. At first when I got to Olivine City I didn't know that there was a Gym Leader that comes before Jasmine so when I got to her gym and she wasn't there I got angry and just went ahead to Cianwood City. So when I did I found the Gym Leader Chuck and defeated him, then I went back to Olivine City hoping Jasmine would be there and she wasn't so I went to Mahogany Town and defeated the Gym Leader Pryce. Then I found that annoying candy bar salesman bought a candy bar and after I did he just wouldn't let me through no matter what and then back at Olivine City someone told me Jasmine was in the Lighthouse caring for a Pokemon. So I went to the Lighthouse got through it and then she tells me to go all the way back to Cianwood City just to get Ampharos some medicine. After I did that I gave Jasmine the medicine and then she finally went back to her gym. Then I went to her gym defeated her and got the 7th Gym Badge. As soon as I did all that I went back to Mahogany Town and that salesman finally let me through.
you need hm whirlpool.
Go to Mahogany town. Go to your left, past the man who sells RageCandyBars. If he doesn't let you through, even if you've bought a candy bar, you have to beat the Cianwood Gym, Olivine Gym, and the Mahogany Gym. Then you have to beat Team Rocket in Goldenrod City, inside the Radio Tower. If you've done all that, then just go past the man who sells those candy bars and keep heading left. You can use the upper or lower path (doesn't matter) but both have Trainers on them. Once you've gone as far left as you can, you'll see a cave entrance (the Ice Path cave). Make your way through it and you'll be in Blackthorn City. Hope this helps!
you have to catch lugia at whirl islands.
you have to beat team rocket in mahogany town.
there are two things you have to do disabandon team rocket and battle the red gyarodos
Get the seven gym badges, run Team Rocket out of Mahogany Town and Goldenrod City then go back through and you should be able to go past.
Distact the man selling the candybars
past the rage candy bar dealer in mahogany town (right of the town) to the ice cave
so you can get past the guy in mahogany town
You will have to beat team rocket twice 1st at then at goldenrod city then you buy candy from him i don't know who or what to give it to but hope all of this help thx
You and lance beat team rockets under-ground base.
you have to defeat the other seven gyms to pass to the next city next to mahogany.
you need to beat olivine and cianwood gym. Then go into one of the houses in maghogany town.You will meet lance a trainer and he reveals a staircase to the team rocket hq.You need to beet team rocket and then maghogany gym.He should then let you past IF THIS DOSN'T HELP VISIT WWW.MARRILAND.COM AND CLICK ON HEARTGOLD AND SOULSILVER WALKTROUGH.
To get past you need to have: Beat Team Rocket in Mahogany (Lance found at the Lake of Rage will tell you where the entrance is) Beat Team Rocket in Goldenrod Beat the gym leader of Mahogany, Pyrce.