A giant engineer named André helps the little people develop a new power source—the "Delta Device"—which could power the Spindrift, but during a test the Earthlings are exposed to a burst of radiation. Afterward, they realize they have become invisible to the giants when André's superior, Dr. Berger, comes to the Spindrift camp site yet is not able see the humans right under his nose. As the weird effect begins to grow out of control, it creates strange warps in space and time where the giants become invisible to the humans and Steve becomes trapped in a nightmarish dimension. Note: This episode is also called "The Delta Effect".