This chapter is longer than the first two - you'll explore multiple locations, fight two bosses, and unlock the Mystic Key that opens all those locked doors you've been passing.
Sailing to Elfheim
Board your ship at Pravoka's southern dock. The port is just below town, past the bridge.

Sail south across the sea and dock at the port on the western continent. Elfheim is a short walk inland from here.

Elven Castle
Before heading into town, visit the Elven Castle just north of Elfheim. Inside, you'll find the Elf Prince in a deep sleep. His attendant explains that the dark elf Astos cursed him, and only Matoya might know how to break the spell. You already met Matoya in Pravoka - she needs her Crystal Eye before she can help anyone.

The castle has locked chests you can't open yet. Come back after you get the Mystic Key for a Mythril Hammer, Bronze Gloves, and some Gil.
Elfheim Town
Elfheim sells Level 3 and 4 spells. Haste (4,000 Gil) is the priority - it doubles a character's hits per turn. Cura (1,500 Gil) gives your healer better recovery. Fira and Thundara (1,500 Gil each) upgrade your damage spells for groups of enemies.

The weapon and armor shops here aren't worth much if you grabbed gear in Pravoka. Save your Gil for spells unless you skipped earlier towns.
Western Keep
Head northwest from Elfheim through the forests and mountains. You'll find a ruined castle called Western Keep. A "king" inside asks you to retrieve his Crown from the Marsh Cave to the south. He promises information about Astos in return.

The locked room here contains a Power Staff, Falchion, and Steel Gloves. All three chests have monster ambushes - return with the Mystic Key when you're ready for a fight.
Marsh Cave
The Marsh Cave is southeast of the Western Keep - look for a hole in the ground surrounded by wetlands. This dungeon is three floors deep and filled with enemies that poison. Scorpions, Cobras, and Crawlers all inflict poison - check the bestiary for full enemy stats. Buy 10-15 Antidotes (75 Gil each) before entering. If you have Poisona, bring Antidotes anyway as backup.

Inside the Marsh Cave
Enter and head north first. Take the stairs down to B2 North and grab the treasure from the side rooms - some Gil, a Dagger, and a Potion. Return to B1 and take the southern stairs to B2 South. More treasure rooms here, then stairs in the southeast corner lead to B3.
B3 has the Crown. The chest is in a room second from the left, surrounded by rocks. Before you grab it, clear the other treasure rooms on this floor. Several chests are locked - you'll return for those later with the Mystic Key. See the full Marsh Cave chest guide for all locations.
Enemies on B3 include Ghouls that can paralyze and Shadows weak to Fire. Use Fira to clear undead groups. Heal up before grabbing the Crown.
Piscodemons
When you take the Crown, four Piscodemons ambush you.

After the fight, leave the cave and use a Tent outside. Don't go back to town yet - Western Keep is closer.
Astos
Return to Western Keep with the Crown. When you give it to the king, he reveals his true form: Astos, King of the Dark Elves. He has what you need - Matoya's Crystal Eye.

Defeat Astos and you receive the Crystal Eye. Time to trade it.
Waking the Elf Prince
Sail back north to Matoya's Cave (near the bridge north of Cornelia). Give her the Crystal Eye and she hands over the Jolt Tonic.

Return to the Elven Castle and give the Jolt Tonic to the Prince's attendant. The Prince wakes up and rewards you with the Mystic Key.

Mystic Key Treasures
The Mystic Key opens every locked door you've passed. Cornelia Castle is required - grab the Nitro Powder to progress the story.

- Cornelia Castle - Nitro Powder (required!), Mythril Knife, Saber
- Chaos Shrine - Werebuster, Rune Blade
- Elven Castle - Mythril Hammer, Bronze Gloves
- Western Keep - Power Staff, Falchion, Steel Gloves
- Marsh Cave - Silver Armlet
Mt. Duergar
With the Nitro Powder, sail to the port south of the Chaos Shrine on Cornelia's western coast. Head southwest on foot to find a cave entrance in a ring of mountains. This is Mt. Duergar, home of the dwarves.

Inside, explore the rooms for treasure. The large southern room (unlocked with the Mystic Key) has a Mythril Mail, Wyrmkiller, Great Helm, and more - see the Mt. Duergar chest guide for all locations. Talk to Smyth the blacksmith - he mentions he could forge something special with Adamantite. Remember that for later.
Find Nerrick in the southern tunnel near a dead end. Give him the Nitro Powder and he blows open a canal, connecting the inner sea to the outer ocean. Your ship can now sail anywhere.
Sail through the new canal and head south along the coast. Your next stop is Melmond, a town being destroyed by the rotting earth. Before you go: make sure you have Haste and Cura, stock up on Antidotes and Potions, and grab the Mystic Key treasures for free gear upgrades. Level 12-14 is a good target before tackling the Cavern of Earth.
Treasure Chests
This chapter covers two main dungeons. See the chest guides for full item lists and locations:
- Marsh Cave - 15+ chests across 3 floors (some require Mystic Key)
- Mt. Duergar - 10 chests (large room requires Mystic Key)