So I assume that you have entered the Golmore Jungle and reached Eruyt Village. And I assume that you have realized that Mjrn is in the bowels of the Henne Mines, being controlled by the dark forces of the nethicite.
You must defeat Tiamat in the Henne Mines' northeast end to free Mjrn and get some clues as to what is behind said dark forces. From there you will meet up with Elder Wyrm, a challenging foe to say the least. He is what is keeping you from entering the Paramina Rift -- unless you go into The Feywood first. (I wouldn't recommend doing that, as the monsters in The Feywood are at level 40-plus. However, if you are up to it, you can pretty much enter the area from Golmore Jungle and head directly west, fleeing all the while. ... Eventually you will reach the Paramina Rift.)
Your ultimate destination is Mt. Bur-Omisace, where Ashe and Fran seek to meet with the leader of the holy group there. You will head south from there -- back through the Paramina Rift -- to the Stilshrine of Miriam in order to obtain the Sword of Kings. The Stilshrine contains two mean bosses -- one is a miniboss that doesn't present too many problems, the other is Mateus, a nasty being that can be a good icy ally as an esper. Of course this all brings you back to Mt. Bur-Omisace, and a fight with the mad Judge Bergan.
... I won't tell you too much more but be prepared for a tough trip onto the Mosphoran Highwaste, the Salikawood and then the Phon Coast. It only gets harder from there. ...
