Otherworld: A Rescue Across Time and Space

The protagonist's father, a member of a geological survey team, mysteriously disappeared while on the job. As an adult, the protagonist joined forces with relatives and friends to investigate, and gradually uncovered his mysterious origins and shocking identity. After a series of thrilling and dangerous expeditions, he successfully completed his mission. (An adventure novel with all the essentials: foreign lands, monsters, survival, deduction, suspense, and the supernatural.)