Mushroom Rock Road
Take a few steps forward from the 
Save Sphere, and you’ll spot Logos and Ormi making their way through the area. A few steps further on, you’ll be stopped by Yaibal (shown as “????” when you first encounter him).
He’ll ask whether you’ve forgotten who he is; it does not matter how you answer his question, but if you say that you have forgotten, he will briefly introduce himself as a reminder. Don’t feel bad if you don’t remember him, by the way. He wasn’t in Final Fantasy X; he was only briefly in the cinematic cutscene that takes place between the two games (“Final Fantasy X: Eternal Calm”).
Make sure you accept Yaibal’s request to “run the gauntlet” by selecting “Sure, we’re game.”
If you accidentally decline Yaibal’s request and select “Not right now,” you’ll miss out on a Story Completion Percent scene. You can’t trigger the scene if you come back and accept later.
After accepting, make sure you speak with Clasko before you head towards the Mushroom Rock Road. Clasko is standing right next to Yaibal, so don’t go too far. Clasko has a few lines of dialogue he runs through, but his initial *sigh* is a trigger for some more percent.
You can talk to Clasko over and over again to make sure you’ve triggered the scene, and he’ll keep repeating the line, “You know, all I want is to ride on a chocobo…faster than the wind!”
Mission: Foggy Fiend Frenzy
This is a very straightforward Mission. Work your way across Mushroom Rock Road while dealing with some temporary fog and darkness that obscures your vision. If it’s causing too much trouble, wait for it to clear.
Mushroom Rock Road
| 1 | Ravine Entrance |
During this Mission, though, you have one stopover to make. Use the pathway shown in the screenshot below to head down to the lower level of Mushroom Rock Road.
Warning
Are they defeatable? Yes, but they are extremely difficult to defeat. They have 9999 HP, so even if you can withstand the damage, which isn’t impossible, it’ll still take you forever to bring one down, and it’s just a regular fiend, so the rewards aren’t great. A more efficient option is to just run away from them for now. Press 
on the control pad and select the 
Escape option.
You can learn more about the mechanics of Escaping/Fleeing Battle in the tips and tricks section of the guide.
Ravine
Proceed forward, and you’ll eventually find a Save Sphere at the northern end of the Ravine, where you can save your game, and there are three treasure chests you can find down here. Use the map below to help you find them.
Ravine
 1 |  Turbo Ether |
| 2 | Phoenix Down |
| 3 | Hi-Potion |
| Den of Woe |
Head into the tunnel just north of the Save Sphere to discover the Den of Woe. A few cutscenes take place here.
Visiting the den is completely optional in Chapter 1, which means it’s possible to miss the scenes that take place here. The first plays as soon as you reach the entrance. After it ends, examine the door, then speak to the person who appears behind you and answer “Of course I do!” for the second.
Maroda will say “This place is off-limits. Please leave.” when the scene has concluded.
Ormi will leave 
Crimson Sphere 9 on the ground before he leaves too. You’ll need to collect them all to gain access to the Den of Woe later on in the game, and this one is permanently missable if you don’t visit the Den’s entrance during Chapter 1. The sphere will also give you access to “Crimson Report 1,” which you can watch later for more Story Completion Percent.
Follow the path south, back out of the ravine, and to the main level of Mushroom Rock Road. Continue northward until you reach the lift at the end of the path. Approach the next lift to trigger a short cutscene with Elma. This concludes the Mission, and Elma hands over a 
Glass Buckle accessory and the 
Heart of Flame Garment Grid as your reward.
Before you ride the lift up, grab the treasure chest south of the elevator to pick up a 
Favorite Outfit accessory. Hop on the elevator and ride it up to the Youth League headquarters.
Mushroom Rock Road - Upper Level
| 1 | Favorite Outfit |
Youth League Headquarters
Grab the treasure chest off to the right side of the screen. You can use the map below to help you locate it, just off the side of the cliff. It holds the Restless Sleep Garment Grid, which is only available this chapter.
Walk up to the entrance to the headquarters. You can’t actually get inside right now, but make sure that you talk to Lucil twice.
You can initiate two separate scenes while talking to Lucil.
Talk to her one more time for another conversation.
You can approach her again, if you wish, but she’ll say “I’m very sorry,” and turn you away.
After that, you’ll notice Maechen sitting cross-legged off to the right of the entrance. Talk to him for some more Story Completion Percent.
Warning
Do not interrupt Maechen during his story. Any interruptions, whether you select “Please, go on.” or “Enough, enough!” will prevent you from obtaining the Story Completion from this interaction. Engage Maechen in conversation, and walk away from your controller until he’s done.
Allow Maechen to tell you his story, and don’t interrupt him at all. His story awards a ton of Story Completion Percent. Select “By all means.” when he asks if you want to hear a story. Finally, Maechen will ask to shake Yuna’s hand. Select “Of course.”
Head back over to the Save Sphere and warp back up to the Celsius.
Celsius
Talk to Shinra on the bridge of the ship and select the “Treasure Spheres” option. Watch the “Crimson Report 1” sphere, which counts for some Story Completion Percent.
View Crimson Report 1. You can do this in later chapters as well, but may as well watch it now.
Talk to Buddy, then head back down to Mushroom Rock Road one more time.
Mushroom Rock Road
Look for Clasko on the right side of the road, right there near the Save Sphere.
Clasko is still trying to find himself. At the end of the conversation, he will say…
Make sure you select “The more the merrier!” and let him on board!
Head back up to the Celsius one more time to close out this section of the game.
Celsius
Jump into the elevator and head to the cabin. Head all the way to the back, climb the stairs towards the cots, and look for Clasko staring out the window.
And now you’re off to Djose.
Checking the “Mushroom Rock Road Complete” box adds the Story Completion Percent for the automatic scenes in Mushroom Rock Road.