Leave Freejia and head for the Diamond Mine. Fight your way through the mine and you will come to a locked elevator. There is a laborer to the upper left you can free by cutting his chain. Make sure you free any other laborers you come across in the mines. When you come to a closed door, hit the four switches around it to open the way. When you see the path leading down, go by it and finish clearing out the room.
When you come to the Dark Space, head back left and use Will's Psycho Dash on the wall where you see his hair blowing. The rescued laborer in there will give you 3 red jewels. Head back to the pathway down you walked past earlier. Run down the ramp to get to the other side.
When you come to another Dark Space, change back to Will if you aren't already. Use his Psycho Dash ability on the wall above to create a wall leading to another Dark Space. In there you can get Freedan's Dark Friar ability. Go back to the last room and use the Dark Friar to hit the enemy that was out of Will's reach. Now you will be able to use the ramp to get to the other side. A laborer will give you a key for the elevator near the entrance.
Unlock the elevator and step on the platform you come to. In the right path down you will find a laborer that will give you a key. In the left path down you will find a key on the ground next to a skeleton in the bottom right. Use the 2 keys to open the door. Free the laborers and one will teach you the Memory Melody.
Return to Freejia and play the Memory Melody for Seth. Talk to Erik and he will suggest you all head to see Will's cousin Neil at his cottage. Talk to Neil and take a look at his inventions around the room. The oxygen tank and airplane wings are in the upper left, the camera is to the right and the telescope is on the table.
At the Nazca Plains, wander around talking to everyone. After, you will see a shadow in the bottom left part of the painting. Chase it around then talk to Neil. Answer the left foot then head over there with everyone. Eventually, you will find a buried tile at that spot.
You will find yourself aboard the Sky Garden. There is a Dark Space to the left. Take the upper right path. A treasure chest has a red jewel in it. When you come to an apparent dead end, you can jump off the ledge and you will find yourself on the underside of the Sky Garden.
There is a jump ledge on the bottom left part of the underside to get back to the topside. Get the Crystal Ball from the treasure chest. Back on the underside, there is another jump ledge that leads to an herb. Return to the main area.
Take the bottom right path. Defeat the sword statue and move him out of the way. Use the ramp to jump the gap. You will find a sword statue that is blocking a door. Move him out of the way to find a Dark Space inside. Turn into Freedan. Use his Dark Friar ability to hit enemies that are out of range. Make your way to the Crystal Ball and return to the main area.
Take the bottom left path. You will find a jump ledge that will take you to the underside. There is a red jewel to the left. Hit the switch then return to the topside. The columns blocking the way left will be gone.
You will eventually reach a Dark Space behind some raised columns. Use the jump ledge nearby. Use the Dark Friar ability to hit the switch from the other side of the columns. Enter the Dark Space and turn into Will. Use the small ramp on the part lower area to get up the other ramp.
Use the Psycho Dash ability to destroy the statues. Use the jump ledge to get to the underside. You will find a floor tile switch and a sword statue to the left of it. Move the statue on top of the tile to raise the columns. Return topside and clear the statues with Psycho Dash again. Run down the large ramp right over to the Crystal Ball. Return to the main area.
Take the top left path. Run down the ramp and hold up to reach the jump ramp. At the next ramp, you can stop yourself as you run across the central platform. Head down to find another jump ledge to the underside. To the upper left you can find a Dark Space. Turn into Freedan and hit the sword statue with Dark Friar and destroy the sword when it comes after you. Move the statue up just a bit then go to the left and move it onto the switch to open the way. Take the jump ledge to get to the topside.
Run down the ramp and take the top jump for an herb. Return to the ramp and take the bottom jump for a Crystal Ball. Return to the main area. The main ramp leading back can be reached by taking the top most path on the underside. Put the Crystal Balls into the slots on the floor. Head up the stairs to fight Viper.
Viper
Viper will fly around and occasionally use wind gusts to push you downward. He will also shoot feathers that can break away to cover a large area. Just keep hitting him when he lowers himself in range. You may want to ready Dark Friar when he is not in range. Afterwards, jump off the platform and you will be saved by Neil's airplane.
In the Undersea Palace, you will find Kara in the room to the right along with a red jewel. Take the stairs down then head left. Take the stairs up and head right to get a red jewel. Go back to the last room and take the stairs down. Go all the way right and you will find Lilly.
Leave the room and take the first stairs down you see. After you go down a long flight of stairs, take the stairs up to find a room full of coffins. Have Lilly open the coffin on the left to find a Purification Stone. Go back and take the stairs down. The leftmost door at the end of the hall leads to a red jewel.
Go back and take the stairs in the middle of the hallway down. Take the stairs to the right down. Put the Purification Stone in the fountain. From the Dark Space at the entrance, go back down the stairs. Go left and take the stairs down. Take the first set of stairs to the right down. Get the Seaside Palace key from the man in the room. Use the key on the door to the left of the Dark Space.
Fight your way through Mu. The rock creatures are tough but you can block their stone throws. When you come to a bubble blocking a narrow passage, move it with your powers or just hit it out of the way. Clear the little slimes to open the way. Go past the spikes and Room of Hope. When you come to another bubble in a narrow passage, you will have to pull it back towards you with your telekinesis.
When you come to an area with 2 statues facing a spot just like with the 2 empty treasure chests you came across, search the area where their gaze intersects. Take the statue you find back to the Room of Hope. Place the statue then leave the room. You will notice the water level has dropped. Go back to the area to the north and go down the stairs. There is a Dark Space across some spikes to the left where you can turn into Freedan.
From the stairs, go down to another area. When you get to a blue ramp, position the bounce bubble next to it to get the momentum to run up the ramp. When you get to some spikes blocking the way, you will have to hit the switch and run around past them before they raise back up. You will eventually reach a Dark Space where you can receive Will's Psycho Slider.
Go back and when you see a hole in a wall, use the Psycho Slider on it to get through to the other side. When you defeat some slimes, they will make a statue for you. When you defeat a rock monster, another statue appears. Check the place where their views intersect and you will find a Statue of Hope. Backtrack all the way to the first area you entered in Mu. There is a Psycho Slider shortcut in the north part of the area above the spike barricade area.
Take the stairs down and enter the second Room of Hope. Place the statue and leave the room. You will notice the water level has dropped again. Down from the Room of Hope, you will find a red jewel. Go back through the Psycho Slider shortcut and take the stairs down near the glowing ball sentry.
You will find a chest with a Rama's Statue. Go back and use the Psycho Slider to get through the hole in the wall facing sideways. Go up and you will come to a chest with another Rama's Statue.
Go down from the sideways Psycho Slide wall passage and you will come to a room where you can place the Rama's Statues. You may want to turn into Freedan before you place the statues. Talk to the large statue and the spirits in the room.
Vampires
The two vampires will fly around the room and surround themselves with damaging magic. The best time to attack is when the magic surrounding them fades. They will also shoot beams out in 4 directions. When they stop to pose, they are preparing to fire a large ball of magic. It's best to run back from them when you see that happen. After the Vampires are defeated, diffuse the bomb.