Final Fantasy IV/Watery Pass & Antlion

Watery Pass South
When you enter, to the north are some chests. Head to the left as far as possible, then take the bridge north and speak to Tellah. If you spoke with Rosa in Kaipo, then he will join your party; otherwise, he will send you back. Once you cross that bridge, go to the upper left most corner, and go through the door.

B2F
Head north, as far as possible, then there will be a ladder on a left to climb into the water. Now go as far south as possible, and there will be another ladder to climb back onto land. When you get onto land, cross the bridge immediately to the left and follow the path until you reach a door. Enter the door. In this room is a save point, where you will be automatically led into a cut scene, and your HP/MP will be restored. Leave the room, and go to the right (only one way possible) until you reach the next door.

B3F
Continue down, across the islands and bridges to the left, and continue to the next room. In this room you can go only go north, so follow this path into the next room. There is a bridge north and to the right, follow this bridge and out the door immediately to the right of the bridge. Before going out this door you should retrieve the more powerful sword for Cecil in the chest south of the exit and on the bridge that goes halfway over the ledge. When you leave this door you will be outside. Use a tent if necessary and continue into the next cave.

Waterfalls
In this cave you will see a large waterfall in front of you. Walk straight into the waterfall and you will be brought down to the next level. When you regain control, follow the path to the next door, looking out for the chests to the south to collect stronger armor for Cecil.

Lake
Follow the path to the water (get the chest on the right side which contains the final piece of armor for Cecil). Go straight north toward the waterfall and walk into the place where red tentacles are moving. At this point you will be forced into battle with Octomamm.

Octomamm
Octomamm is weak against Lit. Use Rydia and Tellah to attack him with Lit, and heal your party whenever necessary. Have Cecil attack with his sword. Octomamm will slowly lower his tentacles into the water until defeated. When you defeat him, walk towards the waterfall where his tentacles were and you will be outside the cave.

Damcyan
Walk to the left and up and you will see Damcyan castle in front of you. A cut scene will interrupt when the Red Wings attack the castle. Walk into the castle and travel all the way up until you reach the room with Anna laying on the floor. Once this sequence has completed, Edward will join your party and you will be placed outside the castle to head to the Antlion's Cave.

Find Antlion's Cave
Using the hovercraft go to the northeast corner of the desert and travel across the shallow water. Once on land again, immediately to the south is the Antlion's cave. Get off the hovercraft and enter the cave.

Inside the Cave
Go to the bottom of the room, and then go to the right until you see a door. Enter it. In the next room, follow the only path available until you reach the door at the bottom center of the room. Go through this door, and you will be in the Antlion's lair. Head straight forward up to the Claws in the ground. After the sequence in which Edward attempts to get the SandRuby, you will be entered into battle with the Antlion.

Fight the Antlion
During this battle, any time you attack the Antlion with a weapon, he will counter with a powerful needle attack. For this reason, with Rydia and Edward it is probably better to use magic (and a song for Edward) because of their weak physical attack. When you have completed the battle follow the cave back to the entrance.

Return to Kaipo
Take the hovercraft back toward Damcyan then to the southwest of the desert, and you can cross the rocks back to the desert where Kaipo is. Get off the hovercraft and enter Kaipo. Go to the house with Rosa and use the SandRuby on her. When she awakens she will join your party and you can continue on to Fabul.