As Zidane, go forward, following Garland.

After he passes out and is awakened by Eiko and Vivi he'll fight an Amdusias at first alone and then be joined by Freya and Amarant.

After the fight, you'll join Steiner and Quina in a fight against an Abadon.

Next, you'll fight a Shell Dragon and be joined by Dagger. After this battle, you'll have a party of four once more.

Return to where you started to get a Holy Miter and to have Moorock switch your party members if you wish.

Continue on from where you were until you reach the room with a grid of blue lights. Activating the control panel causes a bridge to appear in the next room but only for 30 seconds. You must avoid the blue lights and cross the bridge before the 30 seconds are up.

The next chalenge is to ascend the elevator. After running back and forth a few times, adjusting the platform angle, the characters not in your party will stay behind to do it for you. To reach the chest at the top with 20007 gil, set it to 1 then 3. Then set it to 4 to get to the next floor.

From the platform, the top and right teleporters allow you to get an Elixir and Carabini Mail. The bottom-left teleporter will allow you to get some Battle Boots, meet Mozme the moogle and then continue.

You'll fight the Silver Dragon first, then Garland, and finally Kuja without any breaks in between. Afterward, take the new path to the teleporter with the eyes. A few scenes later you'll be back in Gaia.