Tracking a stream, Challenger, Veronica, Malone and Marguerite run into a group of Vantu headhunters. There is nowhere to run or hide, except in what looks like an overgrown cave opening. They dash into it only to discover it is man-made, an old, crumbling mine shaft. There's a loud rumbling that leads to a cave-in. Veronica escapes, but the others are trapped inside. Near death from suffocation, they are saved by Garza, part of a group banished to the mine by a plague-like disease, and led by a blind little boy known as The Oracle. The boy decrees our group must remain underground forever, and is unswayed even by Challenger's discovery that the tremors are caused by a sleeping volcano waking up around them. On the outside, Veronica manages to get Roxton and Summerlee from the treehouse, but they meet up with the Vantu again, who are not easily persuaded to let them rescue the others from their mountain prison.