Diffusion (Galaxy Index, Book One)

Jax is the last protector on the planet Sarvu, but he's not the last creature. Every night crawlers ascend from the bowels of the planet to collect and every night Jax retreats to the temple walls. Until, an unexpected stranger falls from the sky in a ship. Together their survival will lead to the secrets of this strange deserted planet and, in-turn, the answer to the galaxies never ending conflict.