Wellfleet Harbor off of Cape Cod Bay features a particularly striking and unusual tidal environment. Central to it's ecosystem are naturally occurring wild Oyster beds and increasingly important shellfish aquaculture grants. During the spring and early summer high tides it is also the meeting place of local populations of two threatened species: Horseshoe Crabs and Diamondback Terrapin Turtles. This film presents the research efforts of scientist, naturalists and local citizens to understand and protect these inhabitants of this fragile harbor in the coastal environment of Cape Cod.