Skythane - Liminal Sky: Oberon Cycle, #1

Jameson Havercamp, a psych from a conservative religious colony, has come to Oberon-unique among the Common Worlds-in search of a rare substance called pith. He's guided through the wilds on his quest by Xander Kinnison, a handsome, cocky wing man with a troubled past. Neither knows that Oberon is facing imminent destruction. Even as the world starts to fall apart around them, they have no idea what's coming-or the bond that will develop between them as they race to avert a cataclysm.
Together, they will journey to uncover the secrets of this strange and singular world, even as it takes them beyond the bounds of reality itself to discover what truly binds them together.