After you get a melody from the haunted piano, you continue on to the vast Yucca Desert.

Explore Yucca Desert

At the Spookane train station, take the train back to Union station. If you got the Super Spray from Duncan's Factory and left it with Minnie, be sure to get it from her (go south on the tracks, then west through Merrysville, then go to the northwest part of Podunk and go northeast from there to return to your house.) Then give Minnie anything that you don't need. You will need 12 free spots in your inventory (each character can hold up to 8 things.) Make sure you have at least $60 with you, but it is recommended to bring more. $200 should be plenty.

Then go to Union Station in Merrysville and walk east on the tracks until you can go north. Keep going north until you can't go any farther north, then go east and down a ramp. Go east and down another ramp, then go east from there to reach Yucca Desert.

The enemies here are tough. Nancy (a.k.a. Jane in the fan translation) can cast PK Freeze γ and starts with high defense, so use Defense Down on her before attacking. Energy Robots can replenish enemies' health, but it explodes when defeated, so don't attack it until all other enemies are gone. If you are having too much trouble, Ninten can use 4th-D Slip (a.k.a. Dimensional Warp in the fan translation) to escape the battles.

Go east and look for a grassy oasis. If you find broken columns sticking up out of the sand, or walls, then you went too far, so go west and look for it again.

At the oasis, make sure that you have 12 empty spots in your inventory, then talk to the man a couple of times say Yes to go on an airplane ride. Take the first route ($5 per person), and pay close attention to the cactus that the airplane circles around. Then go on three more airplane rides (it doesn't matter which route you take) so you have 12 ticket stubs.

Before you show the old man the ticket stubs, go west from the old man's tent until you go past the last piece of dried grass and see a pile of bones. From there, go north to find the cactus that the airplane circled around. Use Telepathy on the cactus with a face to learn the fifth Melody.

Then go south to the bones and east from there to the oasis. Use a Ticket Stub on the old man, then walk up to the tank to get in. While in the tank, enemies can't attack you. You have to ride the tank on sand; if you try to ride on grass, you will get out (but you can get back in). Go east of the oasis and make sure the tank is lined up with the pond in the oasis. Then go east until you reach the walled area. If you find grass instead, go north until you can see the upper end of the grass, then go west to find the walled area.

Ride between the walls to go toward the hole at the top. On the way, a giant robot will attack.

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This robot can't harm you at all because you are in the tank, and your "Fight" command will use the tank's cannon, so just use the Fight command it until it dies.

Unfortunately, the tank is destroyed in the battle. Go north and walk onto the hole to enter the Monkey Grotto.