After you beat dialga there are several things you must do. If done Cresselia appears in your dreams a little while after Cresselia appears you have to do a few things then the night you talk to Lapras Palkia appears and takes you to Spacial Rift.
You get Palkia in a dungeon called spacial rift.
spacial rift
Spacial rift 12f
You find him in spacial rift.
he is at the end of spacial rift which is 20 floors in spacial rift 10 in deep spacial rift
I dont know losers U suck
chatot tells you about palkia and when you go home palkia comes in and brings you to spacial rift.
you have to get hit 99 then it will work.
to complete Explorers of Sky, you need to defeat Darkrai (with Cressilia on your team) in dark crater after defeating Palkia in the spacial rift.
you find them in dungeons and at the keclion store but i think there's some at spacial rift.
The same way you do in Pokemon explorers of time. You have to go to some mission in the spacial rifts then you have to be the person to hit him last, if your partner hits him. It will just say you defeated Palkia, oh and I don't remember how to get the mission on the spacial rift, nor do I know how to get the dungeon. Well, hope I helped. :)
Drowzee is at the top of the Mt Travail dungeon.