Dreadnought

Hilda and Cid are prisoners aboard the Dreadnought. All 10 chests inside are permanently missable, and 2 bestiary entries can only be found in this area.

Boarding the Dreadnought

Head northwest from Altair through Gatrea and past Fynn. It's a long walk through forests and marshland; the overworld enemies here are tougher than what you faced around Kashuan Keep. Ogre Mages cast Sleep and Blizzard 5 on the route, and Land Turtles soak physical hits with their high DEF. Keep your healer's MP topped off.

Save before entering. This is a one-time dungeon with missable chests and bestiary entries.

Show the guards the Pass you picked up in Bafsk Cave to board.

Dreadnought

The Dreadnought has 5 floors, 10 chests, and no bosses. Collect everything before using the Sunfire.

Werepanthers (190 HP, 35 ATK) are the biggest random encounter threat inside. They hit as hard as Ogres but take more punishment. Stunners are new to the bestiary and can Paralyze your party members; Basuna cures it. Helldivers (140 HP) are missable and only appear here, so don't flee from them. But avoid talking to the roaming soldiers on 1F; doing so triggers a Captain fight that's far harder than anything else in the dungeon. Protect and Blink are worth casting before tough rooms.

1F. Go up the stairs in the top left corner for chest 1 (600 Gil). Go back down and take the stairs in the middle going down.

Go right and walk through the wall to find chest 2 (Sleep Blade); a pack of Sergeants, Soldiers, and Magicians guards it. The Sleep Blade inflicts Sleep on hit, making it useful for crowd control in longer fights. Double back upstairs, then head up and right. At the junction, go right and through the door to 2F.

2F. Head down to the split. Go right; follow the path for chest 3 (Hi-Potion) and chest 4 (Potion). Back to the split, head all the way left. Bottom left corner has chest 5 (Dark Bow). Go up, then right, walk down for chest 6 (Thief's Gloves). Head right and open the green gate to find the prison cells.

Cid takes Hilda to safety via his airship. Make your way back to 1F.

3F. Back on 1F, go south to the stairs leading down. Follow the path around to the door and continue downstairs.

4F. Follow the path to the top right corner. Four chests here: Trident, Main Gauche, Ice Shield (monster chest with a Hill Gigas), and Giant's Helm. The Hill Gigas has 750 HP and 100 ATK; it hits harder than most bosses you've fought. Buff with Protect before opening that chest and keep Cure ready. The Trident and Giant's Helm are both solid upgrades worth equipping before you continue. Head to the middle and go up the stairs; follow the doors to 5F.

5F (Engine Room). A maze with guards patrolling the corridors. Soldiers and Sergeants are the only fights here, and neither is a threat at this point. Go right and up, then left; follow the path around the room. Weave through corridors to reach the door at the top.

Destroying the Engine

Open your inventory and select the Sunfire. The engine catches fire immediately. Cid appears and leads your party to his private airship (no walking back through 5F). You escape as the Dreadnought crashes into the ocean.

Your party escapes in an airship that takes you straight back to Altair.

And with the Dreadnought gone, the Empire loses its airship advantage. Back in Altair, talk to Hilda. She'll mention the Dragoons of Deist. The next chapter sends you across the sea to find them. Buy Antidotes and Eye Drops before you leave; the enemies on Deist's island hit with status effects.