Well, get ready for a bitch of a dungeon. This place is so confusing, so, yeah, be prepared. Anyway, as you start out, head west and go up the steps here and continue west and then head south down the stairs at the far end to find a Treasure Chest, which holds a Gold Hairpin. Give it to anyone you wish, then head back up the steps to the north and head east, then go south when you can and grab the Treasure Chest you see to get a Ninja Suit. Give this to Firion, then give his Flame Mail to whoever needs it the most, if Firion had it Equipped, that is. Afterwards, head southwest as far as you can, then head east to find a Doppelgänger of Firion. Talk to it and use the Black Mask on it to have it disappear.
After this, enter the door nearby and then head down the stairs and on this floor, head northeast to find a Treasure Chest, which holds a Power Staff. If anyone is using Staffs, give this to them if you don't have it already, then head east and at the bottom of the wall here, try to pass through it and then grab the Treasure Chest here to get a Flame Lance. Again, if anyone uses Spears, give this to them if they don't have it already. After this, head to the southwest side as far as you can and enter the door you see and then head down the stairs here.
On this floor, head northwest and try to go through the wall here and when you do, grab the Treasure Chest you see to get an Ice Bow. Give this to anyone who uses Bows if they don't have this already, then head southeast as far as you can and go down the steps and grab the Treasure Chest you see to get an Ogrekiller, which is guarded by Bombs. Afterwards, head west and go past the first door you see and continue on and enter the next door you do see and then head down the stairs here. On this floor, follow the path and head north when you can all the way, then head east and then south down the steps and grab the Treasure Chest here to get a Potion, then head west and enter the middle door. In this room, grab the 3 Treasure Chests to get a Gold Needle, Mute Bell and a Phoenix Down.
Next up, exit this room and then head southeast and enter the door here, then go down the stairs. On this floor, grab the Treasure Chest nearby to get a Drain Scroll, which is guarded by Ghosts and it's not that helpful. See, there's this thing called Cure which works oh so much better, but, it's your call, so, use it if you want. After this, head south and then east and go up the steps here, then head northeast and check the wall here and try to go through it. When you do, grab the Treasure Chest to the south to get a Mini Scroll, which is NOT useful at all, so don't bother with it. Then, head north and open the 4 Treasure Chests here to get 4 Potions. Next, head southwest as far as you can go and enter the door in this corner to find 3 Treasure Chests, which hold a Drain Scroll, Osmose Scroll and the Crystal Rod. DEFINITELY use the Osmose Scroll, as it's a life saver and so much better than the shitty Ethers.
Anyway, once you have the Crystal Rod, go ahead and Warp out of this place and outside, head back to Altair now and sell any Items you don't need, restock on what you do need, heal at the Inn and when you're ready, from Altair, look at your Map. You see that ring like area to the west with the yellow square on it? That's where you need to go now. Before you do, though, remove everything off Leila, then head near it on your Ship and as you get near it, your Ship will be sucked into a whirlpool…