TOKYO HIGH TIDE director Murakami Hiroyasu returns to the Tama River estuary to document Yoshida Tadayoshi, who has been conducting independent observations of crabs over a 15-year period. The camera's relentless focus on crabs brings to light a world not visible to the naked eye.  The mud flats of the Tama River are home to a wide variety of crabs. Yoshida makes regular visits to these mud flats and records his observations on crab ecology. The film reveals the surprising behavior of crabs through fieldwork documenting Yoshida and the mud flats.