Ziggy and the other members of the Black Dinosaurs go to space camp where they learn about the space program and speculate about the existence of extraterrestrial beings.
After the neighborhood basketball court is vandalized, Ziggy and his friends decide to form a club called the Black Dinosaurs and build their clubhouse in Ziggy's backyard.
Ziggy and the rest of the Black Dinosaurs are thrilled to find out that there is a tunnel under their school that was once used by the Underground Railroad, and decide to check it out.