Sky blue where?

[tyranitar.armaldo]

I have been doing tons of missons on mystery dungeon but the sky blue plains reward never comes up. Does anyone know what mission I have to do to obtain it. Also does anyone know how to get the dungeon where lugia resides? Because I have recruited the legendary birds and nothings happened.

[Scepgatr]

You may request a mission with Sky Blue Plains Friend Area here. To activate Lugia's dungeon, try talking to Spinda first. After that, it should get unlocked.

[Cubed]

Following on what Scepgatr said, after you have talked to Spinda (which, to happen, you need to beat Ho-oh), he will leave. You go away, come back, and Alakazam should be near where Spinda is. Talk to him, go to The Legendary Birds' friend area, and you can go to Lugia.

[Scepgatr]

You don't need to beat Ho-oh (or even the three beasts). You just need to talk to Spinda. Go away and come back, Alakazam should be floating in a different place (i.e not in between the Persian and Wigglytuff). For some reason, simply talking to Spinda affects the dungeons and gets Silver Trench unlocked.

[Ultimate Glalie]

Here is a mission you can do to unlock Sky Blue Plains:

Client: Ariados
Objective: Help me.
Place: Mt. Blaze 1F
Difficulty: C
Reward: Mobile Scarf + Sky Blue Plains
Wonder Mail:
2?29 HK0? ?R?C
97?+ 6516 PQ?W