In a remote jungle, off the edge of Lake Nicaragua, a poor fisherman catches the fish of a lifetime, a four hundred pound bull shark. The fisherman tries to sell his catch to the cook of a freighter, something he has done before.As the big fish is brought aboard the ships kitchen, the stretcher they use to carry it snaps and the fish slides headlong across the steel floor plates and crashes under the sink, where a loose plate pivots, sending the body of the shark into the dark bilge below.There are two surprises, the fish is not dead and she is pregnant with twelve live born sharks. The sharks eat the body of the mother and a host of bilge rats on the voyage North to Lake Erie and the steel mills of Detroit and Cleveland.Thirty miles away from Cleveland on the way to their last stop, Detroit, the ageing ship strikes a hard rock shoal off of the coast of Ohio. The twenty foot gash in the hull opens a new and existing world to the sharks, which are nearly a year old due to repairs and legal problems of the ships owners.The wreck in late November, when the water is traditionally low, was preceded by an unu-sual event called a "Polar Vortex". This rare change of weather brings temperatures of -14 below and the freezing of Lake Erie for the winter.The sharks first explore and then dominate their new world, feasting voraciously on the lo-cal walleye and steelhead trout populations. The fresh water and their internal cycling of it puts their metabolism on steroids. The unlimited supply of easy food and the constant recycling of fresh water out of their systems, causes the sharks to grow at an unattainable rate in nature.The spring thaw opens a new world to the sharks, a bright and green water world where there is other food than walleye and trout; there is a new food source abundant upon the surface, a mammal with salt sweat and warm flesh, not that much unlike the rats in their birthplace, the bilge.Winter is waning and the ice is melted by mid-April. The new season will introduce a fierce, new predator in the waters. The "Pack", now twelve strong and over a thousand pounds each, are waiting for the warmer waters of spring and the arrival of humans on the water. The lake has a new predator it hasn't seen since the ice age, large sharks, bull sharks, sharks of the worst kind; hungry, strong, and above all, mean spirited by nature, a perfect cold blooded killer.