The pair of beavers who live next to Big River Junkyard don't agree on much. But when the factory upstream starts polluting the water, they both know something needs to change. Can the Tinkerers design a solution that will make them both happy? In each story in this series, the Tinkerers put on their engineering caps to come up with creative solutions to help others in their world. Along the way, they explore topics that align with Common Core and Next Generation Science Standards.