Alpine Crossing

Alpine Crossing is a location in southeastern Angara. It is a clifflike area that is passed through in Golden Sun. Saturos' party passes through here and triggers a landslide that blocks Isaac's party and forces Isaac to go through Altin and Altin Peak. Afterwards, when Isaac gets the Reveal and Lift Psynergies, Isaac may return to help a character named Hsu that the landslide injured and trapped under a boulder. Doing this will cause Feizhi to give Felix's party the Golden Ring in Golden Sun: The Lost Age.

Walkthrough
Heading west from Xian, you'll enter this area when passing between two mountains on the world map. As soon as you do, Feizhi will run in after you and declare that boulders falling from the mountains have sealed the path to Lama Temple, where Hsu, the man she is looking for, was. Once her cutscene ends, walk back to the split in the path: The North heads to Altin, the southwestern path that is blocked leads to Lama Temple, and of course east is Xian. Before going on, switch your Djinn around so that one character has Growth, and use it on the leafy green plant near the sign. Walk south and freeze the puddle near Feizhi. Climb up, slide down the wall next to it, then jump across the ice pillar and get the chest. It contains Power Bread, which boosts max HP. This is a great item to use on Ivan or Mia. Jump back across, slide down so that you land next to Feizhi, and then exit to the North, leading to Altin.

When approaching from the Lama Temple side, you can see Hsu trapped under a boulder, and Feizhi and Hama standing nearby. To reach them, use Reveal and enter the door that appears. Come out on the other side, and a cutscene begins. When it ends, walk around to the side of Hsu that is opposite Hama, and use Lift on the boulder. Feizhi and Hama pull Hsu free, and you are instantly warped back to Lama Temple. Now, whenever you pass through the crossing, the boulders have been cleared and one can move from Lama Temple to Altin or Xian with ease.

After you've done this, there's many towns you may want to revisit with your Reveal ability. Unfortunately, you can't go back through the Mogall Forest at this point, so you'll have to continue on.