Instructions
Go to the southwest on the island until you encounter a passage between the mountains that is blocked by ice.
Build a "Fire Tower" in front of the ice block. The tower will shoot at the block until it is melted enough for the scouts to get through the passage.
Head south again until the scout encounters another passage blocked by ice. Beware of Yetis attacking the scout and villagers. Send along warriors to fight the Yetis.
Build another Fire Tower in front of this passage to shoot at the ice and melt it.
Head southeast. In this area of the map is the boss, Totem Beast, that warriors may have to defeat in order for scouts to pass.
Look for a "Guide Stone" along the mountains in this area. It will say "Secret Passage" when clicked on. Below this stone is the passage through the mountains.
Place a "Flag" on the hidden right side of the map beyond the secret passage. This will direct the scouts through the passage and into the hidden area of the map.