So, assuming you went ahead finished off the Country of the Musketeers, time to go for the other world.
When Sora dives in, you need to get 900 Prize Points in 85 seconds. It’s fairly easy, as usual.
Symphony of Sorcery
Once Sora arrives, we find Mickey exhibiting his magical prowess, to Sora’s complete amazement. Then a Nightmare comes and knocks Sora out. Man, this is happening a lot lately!
Sora awakens in Yen Sid’s tower, but obviously the Sleeping World one - his clothes didn’t change, but he doesn’t notice. He turns around to find Mickey sitting in the chair enveloped in darkness, as is his music book. Sora attacks the latter to no avail - unless self-inflicted pain was his goal.
Suddenly, Mickey psychically speaks with Sora with wonder at Sora’s Keyblade and wonders who is his master. Sora finds out the obvious and asks Mickey how he can help, but the book is possessed and no one can get it.
We find that the Nightmare is the Spellican from Traverse Town, and ask how to get a Sound Idea to help Mickey.
Suddenly, another book pops up - apparently, within, you can find a way to banish the darkness. But it, too, has some Nightmares within. You’ll learn about this world’s Reality Shift, Melody Catcher - touch notes when the rings around them close, and drag the notes along the bars.
As for the flashback?
Flashback: The Sorcerers Apprentice
We watch Mickey bring the buckets of water in as part of his training under Yen Sid, then he finds the room to be empty. He puts on Yen Sid’s pointy hat and does a bit of magic. In the background, we see Spellican ride in, too…
Symphony of Sorcery
Once you regain control, use the nearby Save Point and Moogle Shop, then leave the area to the south. Go downstairs and behind their base to the south. Open the chest for a Dream Candy , then continue out of the area.
Investigate the grounds to find an Elixir to the east, and a Block-it Chocolate 3 to the west. To the far west is a Portal from Zidane; use it and win in 20 seconds or less to win 25 DP , a Grim Fantasy , and a Block-it Chocolate 3 . Afterwards, backtrack to where Mickey is and head into the book.
Inside, at the Cloudwalk - yay, more physics-defying acts! - go along the linear path for a bit. At the end, on a rock, is a weird spewing fountain. Use Reality Shift on it so we can continue. Scale to the top of the big cliff nearby and go across to the chest to the east, which contains Glide !
Remember the cliff we scaled? Return there and use the Special Portal - win using at least three Flowmotion attacks to get 55 DP . a Grim Fantasy , and some Royal Cake . I also ended up with a Pegaslick Recipe , but that may have been an enemy drop.
Go west while gliding from the cliff to reach a chest with some Treasure Goggles . Northeast of there, on a small ledge, is a chest with an Ice Dream Cone 3 . Go north along the path.
At one point, you can opt to get either northeast or southeast. Go southeast a little and scale the cliffs with Flowmotion to reach a cloud; open the chests there for an Elixir and a Paint Gun (White x10) .
Glide west of there to find a chest with an Intrepid Fantasy atop a cloud. Scale the cliff nearby with Flowmotion, then glide onto the big northern cloud, then go southeast to a chest with a Prism Windmill .
Go southeast onto the rock ledge and use Reality Shift on the thing there. Continue southeast. On your way down the ledges, be sure to grab the Mega-Potion .
Go back northeast, then ride the rainbow northwest so you can easily continue on to the next area to the north. Here in Glen, when you go forward, you’ll find yourself in an updraft. Go east and open the big chest for Tornado .
Then make your way to the far west - avoid the blue stones on the way that REALLY hurt - and use Reality Shift on the music thing to get rid of the updraft. Hit the ground and go to the northwest corner to find an Ice Dream Cone 3 .
Work your way east and south near the cave where you entered. Open the nearby chest for a Mega-Potion , then use the nearby Portal from Laguna (character in Final Fantasy VIII) if you need some Spirits. I didn’t though - I’d been using the same three since the start and they have about TWICE the level of Sora and Riku.
Head to the far east and use the mini-tornado to get on the ledge so we can continue. Go along the linear path and, at once point, near the second fight you get into, you can scale the wall with Flowmotion to reach a chest with a Royal Cake .
Continue along to the Save Point. Scale the wall to the southeast to find a chest with an Intrepid Fantasy . Then use the Save Point and head to the next area.
In the Fields, go north for a bit, then northeast when the storm starts and, somewhere in the southeast/east-central area is a music thing. Use Reality Shift on it to bring back the sunlight. West of there, you find a chest with a Block-it Chocolate 3 .
Go southeast of the music thing and scale the cliff with Flowmotion to reach a chest with an Electricorn Recipe . Go closer to the south entrance of the area and hug the east wall to find a side path, which has an Epic Fantasy . Return to the center of this first field.
Then go northwest and north to run into another storm. Go east from the small building and scale the cliff to reach a chest with a Panacea . Go up the ledge behind it and use Reality Shift on the music thing to bring back the day once again.
Go northeast to the ground and use the Portal from Squall; win the fight using at least three Flowmotion attacks to get 25 DP , a Wondrous Fancy , and a Block-it Chocolate 3 . Go southwest and grab the Mega-Potion , then go west-northwest and along the dirt path to find a big chest; open this for a Triple Plasma .
Go back east into the open field, then head northeast and north along the linear dirt path to find something. The unknown black-hoodeed man comes up, speaking of how easy it is to slip into slumber. As Sora withdraws the Keyblade, the man speaks of how beautiful the world is, like a dream.
Sora questions as to why he’s being followed, to no avail. Apparently, he is NOT part of the examination. As he leaves, the Sound Idea glows and comes into Sora. He returns to the tower and brings it forth. Sora uses the Keyblade to activate it. However, it seems to have no effect.
Suddenly, Riku’s Sound Idea comes forth and picks up the slack, then the book gets depossessed. So Sora decides to head into the book and defeat the Nightmare, gaining Double Impact in the process. Save and shop, then go into the northwestern book.
Inside, Spellican appears, then runs off, with you following.
Effective : Magnet, Zero Gravity
The fight begins with you chasing after Spellican on a figure-eight track. Keep pressing the Y Button to try and catch up. Dodge any attack that comes your way by jumping - otherwise, you’ll take damage, which won’t be healed until the second half of the battle. The attacks consist of poisonous bubbles and a rock that comes at you. Once you catch up, continue pressing Y until you ram 'im.
The second half has Spellican using a variety of attacks, including lightning, star-throwing, and an extendable sword. Here, the use of your Dash attacks is greatly useful in catching up with the teleporting Spellican. The use of any attack that inflicts Zero Gravity is EXTREMELY useful in stopping his attacks for a fair while as well.
After the fight, it seems Mickey is quite okay, awakened by his spirit self. He takes off the cap and thanks Sora. Then he remembers the water barrels from before and leaves. Suddenly, the Sleeping Keyhole appears and Sora unlocks it, gaining the Counterpoint Keyblade as well…