In Tokyo, a 202-kilogram fish caught off the coast of Japan fetches a record price of US$170,000 at auction. That night a sushi restaurant offers mouth-watering slices of the most delicious fatty parts at the bargain price of $12 each, a seventh of the normal price. But few sushi aficionados have any idea of the effort and dangers involved in providing those gourmet slices of tuna. This documentary exposes the extraordinary world surrounding themost expensive fish in the world, the Bluefin Tuna, known by Japanese fishermen as ‘The Diamond of the Sea’. Thrust right into the thick of the tuna-catching action, we follow the efforts of Mitsuyoshi Takeuchi, a stubborn fishermandelighted to be joined by his 17-year-old son Ryoji, a youngman determined to follow in his father’s footsteps and continue the family tradition.