Jake Ransom

Jake Ransom and the Skull King's Shadow by James Rollins

A mysterious envelope, a glowing artifact, and an explosion that blows out the lights...
Jake Ransom and his older sister, Kady, are suddenly moving through darkness. A few words scrape into his mind, like fingernails digging at the lid of a stone coffin.
"Come to me..."
It's the Skull King, the evil that threatens Calypsos - a strange world where Jake will begin to find his own strenth and the power of friendship. In Calypsos, Jake searches for answers to his parents' disappearance and learns that the Skull King wants him and Kady - dead or alive.

Here's the book trailer.