The Mass, an island-sized creature formed entirely of mutated blood cells, has drifted across the world's oceans for millions of years. It uses sharks - the most efficient predators the planet has ever produced - as extensions of itself to gather food. For the most part, the Mass and its Hunters have avoided contact with the human race, but now it's entered the waters off Bridgewater, Texas, where a film crew is busy shooting a low-budget horror film called Devourer of the Deep. The Mass is about to discover something called human imagination, and the humans are about to learn that battling a monster in real life is a little harder than fighting one on screen.