Buy the friend area called northern range from wigglytuff club

after a few days,before your pokemon wakes up the narrator will say....

"the next morning" or something familiar....

then your pokemon will wake up and go outside.

then, a strange jet-like pokemon will sped off pass your pokemon..

then go to the square, a comotion will began.

after the conversation, northern range and is now open for exploration.

finish it, fight latios and pitfall valley is now open for exploration.

finish it and latias and latios will join your team.