Donny and Bobby, two American boys exploring a forest near a tiny Romanian town, discover a science laboratory in ruins. Adjoining the laboratory is a room with a mysterious tunnel. When the boys come upon a dinosaur that appears to have died quite recently near the laboratory, they look for an explanation in the laboratory files. There they find a paper that says:
“Time does not go in a straight line, from past to present to future, as people think. Rather, it proceeds in a circle around a center in the eternal now . . .”
The boys put together these enigmatic words with the dead dinosaur outside, and wonder if the tunnel holds the answer. Entering the tunnel, their bodies begin to shrink, apparently to nothingness, though their consciousness is unchanged.
Emerging from the tunnel into a beautiful countryside, they meet Hansel, who explains that his father invented this “time tunnel.” Hansel has frequently traveled in time with his father, and shows the boys how to encase themselves in time-light spheres. In the days that follow, the trio enjoys travels backward and forward in time. Along the way the boys gain valuable lessons about history, human behavior, and themselves.