Concealment and a natural 20

[Gonn]

My regular group and I were wondering something. Today we had played a mod wherein I was attacking a Naga that had concealment 20%. I rolled to hit him and I got a natural 20 on the die, but the concealment percent die roll failed. Does this matter?

What I mean is, since the rules state that a natural 20, although may not always crit, it ALWAYS hits? Is this the exception to the rule? Or is it that there's an exact order to when each die is rolled that I'm unaware of? (ie the percent die are rolled first, before my d20)

Thanks in advance. :)

[Shifty]

It always hits, in that you achieved the AC requirement - he has a 80AC then you still landed. The concealment problem remains though, and is a separate issue.

[concerro]

It does not matter what the D20 roll is if you can't beat concealment.

[Gonn]

Thanks guys. :)