When the four cousins climb into a rubber boat and paddle UPSTREAM from their Grandmother's pond they have no idea of the adventure that lies ahead. Once they pass under the small bridge the river carries them into a world of mystery and magic. The beauty gives way to fear and danger as they come upon three evil nixies that lock them in a huge pumpkin and transport them far from home. As the four kids try to get back to their grandmother's pond, they find themselves chased by wild animals, sucked into a swamp, and trapped underground. The further upstream the kids go the more dangerous the enchanted river becomes until the children are fighting for their very lives.

They often lose their way but are drawn back again and again to the water in and around which both good and bad folk live. More evil magic beings torment them and if not for the help of four uncommon friends and the courage of the children themselves they might never find their way home again.