Important: Once you enter Gizamaluke's Grotto, you cannot return to any district in Lindblum, although there is a merchant at the Dragon's Gate, should you need to restock on items.
If you don't recall the location of Gizamaluke's Grotto, it's north and a little east of Qu's Marsh. Basically, from Qu's Marsh, go north to the mountain, then follow it east until you find the opening for Gizamaluke's Grotto. Upon entering, there will be a big door in front of you, that no matter what you do, cannot be opened. To the right is a path that leads to a Burmecian Soldier, who will hand over a Gizamaluke Bell. Return to the door and choose the option to ring the bell, which will open the door. There will be a quick scene here, then you're thrown into a battle with two Type A Black Mages.
They aren't anything special, do take them out and move along, where you want to fight the other Black Mage in the back of the room, who will drop another Gizamaluke Bell. Now, you have a choice of three doors to use the bell on: a large one in the middle, then smaller ones off to each side. Open the left door first and in the left corner of the small circular area, you can find a Bronze Vest. Continue to the end and speak with the Burmecian Soldier to get another Gizamaluke Bell, then return to the remaining two doors. Use the bell on hand on the right door to arrive in a room with a big bell in the middle.
Enemy Alert: There is an enemy called Lamia inside Gizamaluke's Grotto, who can be a big annoying to fight. Not only can it increase its own attack power with Might, but it can use Entice to confuse a party member. Luckily, it doesn't work on female characters, so Freya is safe.
As you walk along the stairs in this big bell room, stick to the upper railing and you should see an exclamation point pop up. This is an item, a pair of Mythril Gloves, so make sure you grab them. Continue along and when you go through the little underpass, there will be another item there, a Magus Hat. This is nice for Vivi, as it will teach him the Slow spell, which can definitely come in handy in the long run. In the center of the room, there will be a scene with some moogles. The one wants the Kupo Nut you got back in Lindblum, so hand it over and the bell in the middle will be lifted, exposing a chest. This chest contains another Gizamaluke Bell.
Use the bell on the right door in this room to find the two moogles, with the female one being the save point. Select the Mognet option to read a letter from Moodon to Mogmi, which talks about the Festival of the Hunt. Leave the room via where you enter and on your way out, Moguta will hand over a Holy Bell. Go back into the room with the giant bell and use the Holy Bell on the left door here, where you will face the boss.
Warning: Climbing the vine in the room with the moogles will put you in an area with high level enemies, one of which is the Grand Dragon. If you can manage to inflict it with Heat from Quina's Mustard Bomb, then you could potentially get some nice experience. Also, you could use Limit Glove to deal 9,999 damage, but this requires Quina's HP to be at 1, which is only possible by using a Phoenix Down on him/her and hoping s/he revives at 1 HP.
BOSS - Gizamaluke
Gizamaluke is definitely a more challenging boss than the ones preceding it, but there are options available to you that will help a lot. As the battle begins, you will want to try and toss a Tent at the boss to try to inflict some ailments on it, particularly Silence and Darkness. This will make the boss' most devastating attack, Water, completely useless and it will miss a lot with Crash, its physical attack. Gizamaluke is fairly simple in its attack pattern, as it will use Water and Crash throughout the majority of the fight.
Should you attack with magic (it is weak to Thunder), then it will counter with Silent Voice, silencing that character. At some point during the fight, it will begin using Water on all characters, making it harder on your end, since you lack an actual healer and have to resort to using Potions/Hi-Potions. Like the bosses before it, Gizamaluke has some nice items to steal, including an Elixir, Magus Hat and an Ice Staff. You probably want the last one, although it's in the rare slot, so it can take a while to get it. With both ailments on the boss, it's a fairly easy battle and will eventually be over in no time.
Grand Citadel South Gate
After finishing off Gizamaluke, the game will switch you over to Steiner at the South Gate. When you have control, head up the guards and after a close call, you will be allowed inside of the gate. Once inside, head to the left side and open the chest there for a Multina Racket. Steiner is looking for a place to free Dagger, but there are two people in the way of the alley in the upper right. Speak with the lady first and pick an option, which should get her out of the way. Talk to the green NPC by the gate on the left side, pick either option, then talk to the Chief Engineer in the bottom right.
This will cause him to get out of the way, clearing entry into the alley, but as you head there, a guard comes into the area and asks you to come to him. He'll drop a Gate Pass on the ground and you'll automatically pick it up. Return to the alley and you'll finally let Dagger out of the sack. With both Dagger and Steiner back in control, use this to equip them with any items you have left over in your inventory. There will be a treasure chest on the left side of the screen in this new area, which contains a Potion, plus there is also a moogle here. This moogle, Grimo, has a letter for you to deliver to Nazna, so make sure you check the Mognet option.
Lastly, if you are in need of restocking items, there is a merchant on the right side of this area. When you're ready to continue the story, climb the stairs and speak to the conductor to board the vehicle. Move to the seats on the right to have the game take over and switch back to Zidane.