A group of young boys rent a boat at an inner-city park and enter a small cave at the edge of the lake.
A group of young boys rent a boat at an inner-city park and enter a small cave at the edge of the lake. When they come out the other side, they find themselves in a new world. Floating down the river each day, they travel progressively further back through history, encountering woolly mammoths, prehistoric rhinoceros, and dinosaurs.
