Scientist and explorer George Challenger learns from a dying colleague of a prehistoric world and organizes an expedition to find it.

Desperate to escape and more than a little greedy, Marguerite offers Veronica to a tribal chief in return for jewels and safe passage off the plateau for her group.

When Roxton is running from a tyrannosaur, the earth suddenly swallows him up; the party follows a river to an underground ocean.

Christecs brand Summerlee a devil after he revives a drowning child.

A vampire bite elevates Roxton's hunting instincts to a bloodthirsty level; a smitten native will fight Malone to the death for Veronica.