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

Drakul and the Raiders shoot down the adventurers' balloon, beginning a game of cat and mouse.

The friends emerge from battle to find that one of their number is lost, and goons have enslaved a village.

Captured by lizard men, Malone, Marguerite and Roxton are forced to fight as gladiators in the arena.

During a thunderstorm visions of Summerlee, their lost colleague, lead the friends to the brink of destruction.