as Trevor Anderson: The determined scientist and protective uncle.

Forests of towering fungi unlike anything on the surface.

Convinced that the book contains real clues to Max's disappearance, the duo travels to Iceland. There, they hire a local mountain guide named Hannah (). During a storm, the trio gets trapped in a cavern and discovers a path leading miles below the surface to a "world within a world". To escape, they must navigate a dangerous prehistoric landscape filled with: