Question

I didn't manage to defeat N's dad after I passed the elite four in P W and now I can't get into the league again. What I do? Do I have to go somewhere else first?

Comments

White doesn't mention N's dad. Do you mean Ghetsis?

Answer 1

Go into the leauge Pokemon center and there will be a team plasma grunt. Talk to him and he will teleport you to the castle, after that head back up and you can continue to fight Ghestis.