After you meet Queen Mary in Magicant, you need to find a way back to your world.

Underground Magicant Cave

After you jump down the correct well in Magicant, you arrive in the Crystal Cavern.

There are many dead ends in this maze. To go to the correct area, walk onto the following holes: Right, Left, Left, Right.

If you went the correct way, you will be in a new area. Go south, then east to find a present that contains a Magic Herb. From there, go southwest (you will see a dragon on the other side of the wall) and follow the path to find a present that contains a PSI Stone. You can use the PSI Stone to recover 20 PP. You can use it several times, but eventually it becomes used up and disappears from your inventory.

Go northeast, but don't bother going to that dragon that you saw earlier. If you talk to it, it will say that you don't yet have the power to wake the dragon.

When you go to the right, you will see a hole in the ground. Walk onto it. This will start a boss battle with The Fish.

The Fish

This battle should not be particularly challenging, especially if you bought the upgraded equipment in Magicant. Keep an eye on how much damage The Fish does with each attack, and heal up to prevent your HP from getting too low.

Find the Forgotten Man

After you defeat the fish, you will be in a room with a present. Open the present to get the Onyx Hook. You can use this item to warp back to Magicant any time.

Go up the ladder, then go northeast. When you can, go west, and you will find a present that contains a Sword. You can't equip it, but it will be helpful later.

Go north from there, then west. You will find a man standing in a doorway. Talk to him several times. When he asks if you are a forgotten man too, say No. When he asks you to ignore him like everyone else, say Yes. Then he will disappear, and you can go through the door.

XX Cave 2

You will now be in XX Cave 2, which looks a lot like XX Cave 1, but isn't the same. Go outside. You'll see a building to the left, but you should ignore it for now. Make your way north. Later, you will see a group of trees in this shape:

 XXX
X X X

Go northwest from there, then go down the ramp below. From there, go north to reach the town of Merrysville.