Desert Shadows - Joshua Dowidat - Bog

For Caleb and Liam, a pair of close-knit brothers who have trouble fitting in at school, the Southwest desert around their home offers a place where their imaginations can run wild.
But as their explorations take them farther from home, a sinister darkness begins to invade their happy adventures -- a darkness that is far more real than what their imaginations can conjure up. And when they collect souvenirs from an abandoned house that turn out to be powerful talismans connected to a mysterious shadow land, strange events and people begin intruding into their lives. Along the way, the brothers acquire some new friends -- including two ghosts and a reclusive neighbor -- who give them valuable insights into the darkness they are fighting.
Will the evil from the shadow land gain control over Liam and Caleb so that the doorway to Earth remains open? Or will they learn to keep the secrets necessary to survive and become free from the evil that is attempting to absorb them into its dimension?