A young boy sits atop a fishing rig on a small boat, its rod arced under tension. The film cuts, and we see the boy turn to his father with a victorious balled fist, as he regards his catch—a small thresher shark—lashed to the side of the boat. In the background a local pop tune croons out of a radio, mingling with the sounds of the sea below and seagulls above.  

Then the camera catches something in the water beyond: a fin the color of soot, tracking the boat. Seconds later a black head the shape of a torpedo breaks the water and attacks the fisherman’s prize. The water becomes a maelstrom of foam and blood