After getting a clue from Alanna's nursery rhyme about the Right Knight, you should head northwest to Doomingale Forest.
Go to Doomingale Forest to reach Brigadoom
Go northwest from the town of Zere to reach Doomingale Forest. There are poisonous ponds in the area, so try to avoid them.
As you go toward Brigadoom, you might encounter a stairway that is blocked by some poisonous water. You can avoid stepping through that if you go to the east and up some stairs.
Once you reach Brigadoom, you will find the Wight Knight there. After he talks to you, you can explore Brigadoom.
If you go to the southwest corner of the area, the path leads you to a tower with a blue chest in it. After you get this chest, go outside, go south, and then go northeast into the ruins.
Go north until you can go east, then go north, and you find a door. Go through and go up the stairs to find a red chest that contains a Trailblazing Bandana.
Go back downstairs and go outside, then go west to find a blue chest.
If you go north, then west, you find stairs leading down to the basement. Go north and then east, and use the eastern path to find two red chests, which contain a pair of clogs and a Mini Medal.
Go back the way you came until you can go south. There are some stairs to the left. You can optionally go south to find a red chest that contains a Belle cap, but you eventually reach a locked door, so go back north and use the stairs on the left.
You will now be in Western Tower. There are some dressers to the north that you can open for a chance to find items, and a jar to the south that you can break, but otherwise, you should just go up the set of stairs next to where you entered this area.
Go south and unlock the door. Then go north and follow the path. You can optionally go past the door in the north wall to find some barrels to break for a chance to find items. Otherwise, go through the north door and down the stairs beyond.
If you go east you find some stairs leading down. You can go down the stairs to find a red chest that contains Gold Bracer, as well as a portrait on the wall, a letter in the bookshelf, and a diary on the table.
Go back upstairs and make your way clockwise around the room until you see a door to the north. Go through.
The Wight Knight will appear, and so will Morag. After some things happen, you will have to fight Morag. Talk to her to start the battle.
Morag knows some magic, like Crack, and she also has an ability to dance. Mostly, she will just hit you with her knife. It should not be too difficult to defeat her.
Return to Stornway
Talk to the Wight Knight after Morag is dead, and some things will happen. Talk to Simona afterward.
Then if you have a Chimaera Wing, you can go south to go outside, and use a Chimaera Wing there to teleport back to Stornway. If you don't have a Chimaera Wing, go anticlockwise and up the stairs, then go south and west. From there you can go south and leave Brigadoom, then go southeast to Zere, where you can purchase a Chimaera Wing to teleport back to Stornway.
Back in Stornway, go talk to the King, and he will unlock the treasure room for you. Go up the stairs behind the throne and go east to the treasure room to get some Aggressence, 1000 gold coins, and a Gold Rosary. There are also two blue chests here.
When you leave the castle, there will be a cutscene.
Be sure to visit the Inn before you leave. Erinn found an alchemy pot. Since you are a Celestrian, you can talk to it. It calls itself Krak Pot. To use it, move the cursor to a recipe, and the needed ingredients will be listed in the top screen. If you have the ingredients, you can create the item. You can find recipes all over the world, so be sure to talk to everybody and check every bookshelf. You can also use the "try your luck" option, which will allow you to select ingredients freely, and if your ingredients make a valid recipe, you will create the item. You won't lose ingredients if the recipe is invalid.
Now that you can use Krak Pot, you will find Bill standing near the signpost in the center of town. He has a mission asking you to make a Panacea. He will give you the recipe. You can purchase Moonwort Bulbs in Zere.
Recipes You Can Make Now
You can unlock a recipe now if you talk to Bill in the Stornway Plaza and accept his quest (#004), and you will learn more recipes upon completing the quest.
Check the Starflight Express
Before you can proceed, you have to return to the Starflight Express, so go northwest from Stornway town and use the northwest exit to return to the mountain pass. Follow the path through the area and approach the Starflight Express, and there will be a cutscene. Afterward, go through the door to enter the train and there will be another cutscene. Afteward, exit the train, then go north, then northeast to return to the Western Stornway area.
The king has opened the gate that is in the northeast part of the Western Stornway region, so you should go there next. You can talk to the soldier in the building on the bridge to get a mission. Cross the bridge to reach Coffinwell.