Trama

Challenger has made a windmill to produce electricity, a storm brews and ball lightning creates a portal that allows a helicopter with engine trouble to come through from the year 2000. This brings up the question of time travel once more.

Challenger is trying to harness the energy of the wind to generate electric power for the treehouse when a storm erupts and a gigantic ball of lightning strikes Challenger's windmill. In the ensuing silence, the sputtering sound of a small engine is heard, and a helicopter appears in the distant sky. It draws nearer and lands in the clearing - all on board, a family of 20th century tourists and their pilot, survive. As Challenger and the others marvel at the new arrivals, Marguerite tries to come up with a way to escape the plateau in the helicopter, at the expense of the others if need be. Meanwhile, a hostile tribe has also seen the smoking helicopter land and want to make it theirs, resorting to a kidnapping as a means of achieving that goal.

Challenger is trying to harness the energy of lightning when a gigantic bolt splits the sky. In a blinding flash, the ground is scorched, and by some miracle, no one is injured. In the silence after the thunder, the sputtering sound of a small engine is heard, and a small plane appears in the distant sky. It drops from view, crashing into the jungle. All survive: four modern day tourists - a couple, a middle-aged man and a gorgeous young woman. The group are set upon by a hostile tribe and taken prisoner. Our explorers arrive to find only the disabled plane, which Challenger and Malone set about trying to repair. Kenner, the leader of the hostile tribe, is fascinated by his captives but keeps them in a dungeon. Roxton and Veronica devise a plan to save them.