It almost goes without saying that a book about exploring Antarctica belongs to the adventure genre. The story moves at a quick pace, with the extreme climate (and the baddies) providing a constant sense of danger. On the surface, our characters are on a quest to find Symmes's Hole, a secret portal to the center of the earth. Since that place doesn't actually exist, the more important quest is ultimately an internal one: Sym's struggle to come to terms with her father's death.
Though the external landscape of Antarctica is a fascinating one, we readers also spend a lot of time exploring another interesting terrain—Sym's psyche. Her interior landscape is just as fascinating as the icy external one. Elements of mystery surrounding other characters' motivations help add to the book's strong sense of suspense. For a long time, we wonder whether Victor is an eccentric scientist or a crazed murderer. He is of course the latter, but figuring that out is part of the fun.