Mike: My name is Mike Nelson. My job, underwater research. In fifteen years of diving, I've had my share of fun and danger. I've had all kinds of playmates. Friendly... and unfriendly. But the most deadly thing that I've ever encountered in the deep wasn't a shark, wasn't a stingray, and it wasn't the poisonous touch of the Portuguese Man-of-War. It was something man-made that almost destroyed a harbor, a village, and a hundred fishing boats.