After the red rock is stolen, you explore the prehistoric world to find it.
Now is a great time to get the equipment they sell at the trading hut. But in order to trade, you need trading goods, right? So... go to the hunting range in the woods north of the village huts and fight monsters there to win trading goods.
In the Hunting Range, you can fight Nus when it rains. The Nu will either show up at the far right in the middle of the screen (on the platform), or by the upper right of the screen, or the upper left. It's best to wait on the platform, and, if the Nu isn't there when it starts raining, run up to the upper right of the screen, then the upper left. The Nu can't kill you -- it can only take your HP down to 1. You get a Third Eye when you beat it for the first time, and every time you beat it, you get 3 each of Petals, Fangs, Horns, and Feathers.
To get all the items in the trading hut, you'll need 9 petals, 15 fangs, 15 horns, and 21 feathers. This gets you three Ruby Vests and Rock Helms. Ayla has those already equipped, but she doesn't stay with you permanently. Alternatively, you can wait until you reach the Reptite Lair, where you'll get another Ruby Vest and Rock Helm.
The items for trade are as follows:
3 Petals, 3 Fangs = Ruby Gun
3 Petals, 3 Horns = Sage Bow
3 Petals, 3 Feathers = Stone Arm
3 Fangs, 3 Horns = Flint Edge
3 Fangs, 3 Feathers = Ruby Vest
3 Horns, 3 Feathers = Rock Helm
The guy in the bottom right hut gives you a Tonic.
Now it's time to go to the Forest Maze (to the south). First, walk up to Kino. Then, open the chest to the right (Mid Tonic). Climb down the vine, hug the left wall, and open the chest (Revive). Climb down the second vine and go right, across the log. Go down for a chest (Mid Tonic), then up and left for another chest (Mid Ether). Keep going, hugging the left wall on the way, and when the path splits, there's a chest to your left (Revive). Continue south. All the way at the bottom of the screen is a chest (Shelter). Then there's a ramp to the right of that chest -- go up, and keep going, hugging the right wall a couple times. When the path splits, go all the way left and get a chest (Mid Tonic), then take the ramp above you. Hug the upper wall and go around the circle hugging the wall. Open the chest at the bottom left (Heal), then climb down the vine. Go right, under a couple ramps for a chest (Mid Ether). Then go back to the left, where the vine is, and go down to exit the maze.
Use a Shelter if you need to, then enter the Reptite's Lair.
In the second room are monsters that drill holes into the floor that take you to the next rooms. What room you end up in depends on where the hole is (see below). You can get back to this big room later, so you can visit different holes later. If you don't like where the monster is digging, you can bump into it to make it stop.
+---------------+---------------+ | 2 Evilweevils | 1 Mid Ether | | | 2 Evilweevils | | | 2 Fly Traps | +---------------+---------------+ | 1 Mid Ether | 1 Full Tonic | | 1 EvilWeevil | 1 Evilweevil | | 1 Fly Trap | 1 Fly Trap | +---------------+---------------+
In the southeast and northeast room, if you let an Evilweevil dig a hole near the right wall, you can access another room down that hole. I had a bit of a hard time reaching the Elixir room below, but I did it.
+---------------+---------------+---------------+ | 1 Megasaur | | 1 Elixir | | | 1 Ruby Vest | | +---------------+ 2 Evilweevils +---------------+ | 1 Full Tonic | 1 Fly Trap | 1 Full Ether | | 1 Evilweevil | | 1 Fly Trap | | 1 Fly Trap | | 2 Evilweevils | | | | 1 Megasaur | +---------------+---------------+---------------+
In this big room, there are Reptites running everywhere. You can just avoid them if you don't want to fight. There are a couple Reptites just standing there -- behind them are chests. Walk behind them to get the chests (top: Full Ether; left: Rock Helm).
If you run up real fast from the entrance, you avoid a fight with the guys below. If you follow behind the Winged Ape and go in the door just above the door where you came in, you can avoid a fight and go back to the upper level and go down those holes again.
Otherwise, go straight up, and run to the side of the Winged Ape as it passes. Save when the save point appears, then go up the stairs.
Go up. It doesn't matter what you tell Azala, he'll summon Nizbel whatever you do.
Use Lightning to lower his defense, then use your best physical attacks. Volt Bite works well (after you've used Lightning). You may be able to get in Volt Bite twice, just be REALLY quick about it. Eventually Nizbel will release the electric energy, hurting you quite a bit. If Robo doesn't know Heal Beam yet, have everyone use a Mid Tonic right after Nizbel releases the energy. After that, you have to use Lightning on him again to lower his defense. Keep HP above 200.
Now go back to Mystic Mountain, all the way up to the ledge where the Gate is. Fall off the ledge into the Gate.