The St Johns River is born in marshes then winds northward for 310 languid miles before flowing through Jacksonville Floridas greatest waterway a haven for manatees and mecca for bass fishing is under siege by a burgeoning human population Its challenges are many but there is great hope This is the story of a river returning Flying inflatable boats cave diving kayaking and a stormdrain spelunking expedition up the great St Johns River bring us closer to understanding the environmental challenges facing Americas waterways