Off the easternmost corner of India, in the Bay of Bengal, lies the immense labyrinth of tiny islands known as the Sundarbans, where settlers live in fear of drowning tides and man-eating tigers. Piya Roy, a young American marine biologist of Indian descent, arrives in this lush, treacherous landscape in search of a rare species of river dolphin and enlists the aid of a local fisherman and a translator. Together the three of them launch into the elaborate backwaters, drawn unawares into the powerful political undercurrents of this isolated corner of the world that exact a personal toll as fierce as the tides.