In Jules Verne's classic tale Professor Von Hardwigg and his nephew Harry discover the entrance to an ancient volcanic tunnel in Iceland. They choose to explore it for the mysteries it may hold, the Professor for scientific knowledge, and Harry to prove his bravery to a beautiful girl. It is a dangerous journey that may destroy them both. As they travel deep into the caverns they encounter a subterranean world that pre-existed man. It is an adventure as fascinating and strange as any explorer ever recorded. Finally, with their equipment lost and food running low they must face the consequences of a vital choice; attempt returning to the world above, or explore even deeper mysteries in hopes of rescue.