Henderson, D: Khalia's Tomb

On a desolate snowfield high in the icebound passes of a towering mountain range, the fugitive Guardian Mahleena clings desperately to the rim of a bottomless crevasse. Her fingers are slipping on the frozen ground. She can't hold on any longer. Death is coming for her.
Her only hope of survival is to abandon the sacred artefact she has carried half-way across the world - Khalia, one of the thirteen off-world Skulls of Light that once graced the Pyramid Temple in Atlantis. The bag that holds Khalia is on Mahleena's shoulder, dragging her towards oblivion.
But can Mahleena sacrifice Khalia to save her own life?
As for me? I'm on a rescue mission. My friend Callum's life is in danger. He needs my help, but I don't know where he is. I can only pray I'll find him in time.
And, as usual, nothing is quite as it seems...