No Immortal Bones

Jiang Yuan, a young man of the Mountain-Back Clan, watches as his younger sister is chosen as an immortal seed and sent to the Moon Palace. Three years later, all that comes back is an empty travel bag. He climbs to the heavens along the broken Heavenly Ladder, only to discover that ascension isn't becoming an immortal: it's a process of selection. The Moon Palace isn't an immortal realm, but a ship.